NABTEB Questions And Answers For Biology all for you. Note that the NABTEB Questions and Answers below are not NABTEB Expo or 2021 Real Questions. They are Questions That NABTEB has set before. They will go a long way to help you Pass the 2021 NABTEB Biology.
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PART I: Introduction
(a) Mention FIVE beneficial uses of bacteria.
1. The decaying of dead organic material into humus which serve as plant
2. The production of composite manure.
3. Conversion of atmospheric nitrogen to nitrates through ammonia and
nitrites, demystification of nitrates.
4. Vinegar making from alcohol.
5. Tanning of leather
6. Pitting of flax or jute
7. Curing of tobacco
8. Butter/Cheese/Cream making
9. Making vitamin B and K in large intestine of man
10. Digestion of cellulose in ruminants
11. Turning of sewage into fertilizer
12. Vaccine making by using weakened bacteria
13. Production of biogas
(b) State THREE places each where:
i. Viruses may be found
Air, Soil, water, saliva, blood plasma, semen. cells
ii. Bacteria may be found
Air, soil, water, dirt under the fingernail, in the body of living
things, toilet/latrine, compost, gutter.
(c) State briefly the various methods that can be adopted in the prevention of
viral disease in:
1. Stocking the farm with healthy animals
2. Feeding the animals with clean food
3. Keeping the animal in clean and tidy habnitat
4. Vaccinating the animals against viral disease
5. Raising disease resistant species or animals
6. Isolation of infected animals
7. Use of quarantine services.
1. Using the right planting distance, method and season.
2. Removing and destroying infected plants
3. spraying plants with pesticides at the right time
4. growing disease resistant crops
5. planting healthy seeds, seedlings and stem cuttings
6. control of vectors (e.g. in cassava mosaic)
PART II: Flowering and Soil Science
2. (a) Describe the external features of a named monocotyledonous flowering
Oil palm tree, maize, rice, spear grass, sugarcane, onion, plantain, banana,
pineapple, bamboo, arrowroot, cocoyam.
1. roots are numerous, long and slender/fibrous
2. all the roots arise at the same point at the base of the stem
3. stem is long and cylindrical
4. stem shows distinct/clear nodes and internodes
5. stem show no branding, sometime covered by sheathing leaf bases.
6. leaf is long and narrow/slender/linear, with or without sheathing leaf
7. leaf is parallel – veined
8. flowers are small and numerous, usually dull coloured, not sw3eet
9. pendant stamens, feathery stigma on flowers.
(b) What is the role of green algae in an aquatic habitat?
1. primary producer
2. removes excess carbon dioxide
3. returns oxygen to the habitat
4. pollutes water
3. (a) Define the terms:
The process by which green plants manufacture carbohydrates from water and
carbon dioxide using sunlight and giving off oxygen as a by-product.
A process in which oxygen is used to break down organic matter to release
energy in all living cells, while water and carbon dioxide are released as waste
(b) What are the differences between photosynthesis and respiration?
Photosynthesis builds organic compound/anabolic/breaks down organic
1. Stores energy in organic compound 2. carbon dioxide is assimilated/used up 3. oxygen is given off
Releases energy from organic matter Carbon dioxide is released
Takes place in all living cells Takes place both day and night.
(c) Describe ONE mechanism of transportation in plant.
1. Root pressure
2. soil water flows into cell sap or root hairs
3. water in the root hairs moves into xylem vessels through the cortex,
endodermis and per cycle
4. water in the xylem vessels or the root is moved into the xylem of the stem
branches and leave under root pressure. OR
5. Suction pressure/transpiration pull/unbroken water column
6. As water passes from soil into roots, stem and leaves suction pressure is set
7. as excess water is evaporated from the leaves an unbroken water column is
maintained in the xylem vessels
8. as transpiration continues, a transpiration pull is set up.
PART III: Animal Biology
4. (a) Give THREE differences between autotrophic and heterotrophic modes of
Autotrophic Mode of Nutrition
Heterotrophic mode of nutrition
1. the organisms (green plant) make food in their body
The organisms (non-green plant and animals) depends on food made by green plant.
2. possible only in the presence of sunlight
Possible at all times.
3. makes complex organic compounds from simple inorganic materials
Takes in complex organic compounds and break them down into simple absorbable forms
4. food made by the process of photosynthesis and chemosynthesis
Food is taken in by holozonic, saprophytic, symbiotic and parasitic methods.
ii. State THREE differences between parasitic and saprophytic modes of feeding
b. i. State the mechanism involved in the digestion of piece of fish in the
stomach and in the small intestine.
1. Churning/turning/mixing by the stomach wall.
2. Addition of water, enzymes and dilute HCL/Gastric Juice.
3. Relaxation and contraction of the pyloric sphincter at the duodenum.
4. Neutralization of the acid medium from the stomach
5. Addition of water, enzymes and bile.
ii. Name the two reagents used in testing for protein.
1. Million’s reagent
2. Biliret’s reagent
3. Folin’s reagent
4. Xanthoproteic reagent.
5. (a) State FIVE functions of the skeleton.
1. Give shape/form to the body
2. support sort and other part of the body
3. protect delicate organs and structures of the body
4. provides places for attachment of muscles
5. joins the muscles to bring about movement of the body
6. aids breathing
7. manufactures white and red blood cells.
(b) With the aid of diagram describe how the muscles cause bending in a named
i. Elbow joint, knee joint
ii. When the triceps contracts, the biceps relaxes and the arm is stretched.
iii. When biseps contracts, the triceps relaxes and the arm bends at the elbow
iv. The lower arm is brought close to the upper arm.
(c) What aid would you give to a person with a suspected simple fracture of the
i. Encourage the person to lie on his back
ii. Put a splint on either side of the leg.
iii. Bandage or tie the splints away from the injur4ed point.
iv. Use a stretcher to take the person to the nearest hospital
v. Reassure the victim of safety.
PART IV: Genetics and Ecology
6. (a) State FOUR physical characteristics in man, which show variation among
offspring from the same parents.
i. Tallness, shortness, dark complexion, light complexion
ii. Hairy body, baldness, flat nose, pointed nose, thick lips
iii. Gigantism, dwarfism, fatness, thinness, albinism, knock-kneed
iv. Free/attached ear lobe
v. Finger print
(b) Explain briefly ONE way in which the characteristics for tallness is passed
from parent to offspring.
1. The allells for tallness can be homozygous or heterozygous as TT or Tt
2. During gametes formation the genes separate independently
3. Genes of gametes combine randomly during frertilisation
4. A gamete carries only one member of the alleles T or t
5. During fertilization T may combine with t to form a zygote, Tt for
tallness since T for tallness is dominant over t for shortness.
(c) How is the sex of a human embryo determined at fertilisation:
i. The male produces two different types of gametes – Y and X
ii. The female produces only one type of gamete – X
iii. After mating, numerous male gametes surround the female gamete
iv. Some of these male gamete carry Y and other X chromosomes.
v. If the male gamete carrying Y fuses with the female gamete X, the
zygote is XY which is male embryo
vi. If the male gamete carrying X fuses with the female gamete X, the
zygote is XX which is female embryo.
PART I – INTRODUCTORY BIOLOGY
1. (i) Define the term ”˜Osmosis’.
Osmosis is the movement of water molecules, from their area of higher concentration, to
their area of lower concentration through a semi-permeable membrane, until equilibrium is
(ii) Describe an experiment to demonstrate Osmosis using a named living material.
A named living material – egg membrane, urinary bladder, base of pawpaw petiole,
yam cup, pawpaw fruit, yam strip, yam tuber.
Description of the experiment:
1. Cut two thick pieces of yam tuber.
2. Peel off the bark
3. Remove the central portion to make them look like cup.
4. label them A and B
5. stand them side by side in a trough or distilled water.
6. pour some quantity of strong salt solution into A
7. leave B without salt solution to serve as a control
8. allow set-ups to stand for 2 – 4 hours.
1. Water molecules move from the trough into yam cup A,
2. Water level in A rises.
3. Water molecules did not move into yam cup B.
Living tissues of yam as semi permeable membrane allowing water
molecules, to move from area of higher concentration in the trough, to area of
lower concentration in the yam cup A.
Yam Cup B had no salt solution, water molecule did not move into it, its
water concentration was the same as the trough.
(ii) Give THREE physiological processes in animals which are osmosis driven.
i. Movement in and out of water molecules in animal cells
ii. Re-absorption of water in the kidney tubules
iii. Absorption of water from undigested food in large intestine/colon
iv. Haemolysis in red blood cells.
PART II – FLOWERING PLANTS AND SOIL SCIENCE
2. (i) What is photosynthesis?
It is the process of manufacturing organic substance, sugar, in green cells, in the
presence of sunlight, using carbon (IV) oxide, water and dissolved salts, giving
off oxygen; as a by-product.
(ii) Describe an experiment to show that photosynthesis can only take place in the
presence of chlorophyll. (An illustrated diagram is required)
1. Collect a variegated leaf
2. illuminated for about 4 to 6 hours
3. from a healthy growing acalypha/croton/ice plant/calladium plant
4. map the leaf/draw the leaf and label the different coloured areas.
5. treat/prepare the leaf for starch test
6. spread iodine solution on the leaf
7. compare/match the leaf with the map.
1. Green area stained black/blue black
2. Other coloured areas/white/red/yellow stained brown or yellow
1. Green areas contain chlorophyll, carried out photosynthesis, therefore
2. yellow/white/red areas contained no chlorophyll, did not photosynthesize,
stained yellow or brownish.
3. photosynthesis take place only in the presence of chlorophyll.
(iii) List THREE importance of photosynthesis to the living thing.
1. makes food available for all living things
2. makes oxygen available for aerobic respiration
3. removes excess carbon (iv) oxide
4. fibre for making clothes, ropes, mats etc.
(iv) Name TWO storage organs in flowering plants.
1. Root, 2. Stem 3. leaf 4. bulb 5. corm 6. rhizome/flower
3. (a) (i) Name TWO organisms that help in the improvement of soil fertility.
1. putrefying bacteria, nitrifying bacteria, nitrogen fixing bacteria,
blue green algae.
2. Earthworm, termites, mushroom, legumes.
(ii) Discuss the role of ONE of the organisms named above in maintaining soil fertility.
1. The role of putrefying bacteria in maintaining soil fertility.
1. Causes decay: decompose organic remains thereby adding humus/plant nutrients
to the soil, making soil to retain water/moisture. OR
2. Nitrogen fixing bacteria:
i. fix atmospheric nitrogen in the roots of legumes.
ii. change nitrogen to nitrites, in the soil.
iii. nitrigying bacteria change nitrites, in the soil OR
i. burrow/make channels in the soil which improve drainage aeration and
ii. drag leaves into the soil when leaves decay humus is added to the soil.
iii. Form worm caste which improve soil texture
iv. dead worm in the burrow add humus to soil
3(a) iii. State FOUR farming practices used by man to maintain soil fertility.
1. crop rotation
2. shifting/fallowing method
4. mixed farming
5. application of organic manure
6. application of inorganic fertilizer
7. growing of cover crops/legumes.
8. Ridging of farm land
10. ridging across the slope.
3(b) Three measuring cylinders with a funnel on each were placed on a table. The necks of
the funnels were plugged with cotton wool. Equal weight of soil samples were placed in
the funnels as follows: Sand in the first, ground loam in the second, and ground clay in
the third. Equal volume of water was poured in the three set-ups.
i. write the aim of this experiment
ii. state the major observation of this experiment
iii. draw and label the experimental set-ups.
i. to compare water retaining capacity/porosity of different soil types
ii. (a) the major observation of this experiment is that water passes fast through the
ground clay, faster in ground loam and fastest in sand.
(b) Highest volume of water is collected in the cylinder carrying sand.
(c) Less volume of water in the cylinder carrying ground loam
(d) Least volume of water in the cylinder carrying ground clay
(e) Ground clay retains almost all the water
(f) Sand retains very little amount of water
PART III – ANIMAL BIOLOGY
4. (a) i. Make a large and well labelled longitudinal section of the heart of human
being to show its structures.
4. (b) i. Define external respiration.
This is the exchange of gases between the living things and the surrounding.
ii. Define internal respiration.
This is the utilization of oxygen to release energy in stored food giving off
carbon (IV) oxide and water as waste products.
iii. List FOUR characteristics of respiratory surfaces.
Thin, wet/moist, vascularized; ciliated, smooth.
PART IV – GENETICS AND ECOLOGY
5. (a) Define:
1. Ecology: is the study of the interactions of living things with their physical
environment, and with one another.
2. Habitat: is a place where an organism is found/that can sustain/support life.
3. Population: is the total number of organisms, of the same species, living
together in the same place, that can reproduce fertile offspring among
themselves, at a given time.
4. Ecosystem: is the collection of different organisms, living together in a place,
interacting among themselves and the physical environment.
5. Community: is where different population, living together, in the same place
5. (b) Give ONE functions for each of the following tools in the study of ecology.
ii. Sweep Net
iv. Depth Guage
i. Quadrant: for sampling/determing population size frequency and density of a
ii. Sweep Net: for catching/collecting insects
iii. Pooter: for sucking in tiny/minute insects and other animals from tree barks,
leaf and rock surfaces.
iv. Depth Guage: for measuring depth of water in an aquatic habitat.
PART I – INTRODUCTORY BIOLOGY
1 (a) List the FOUR levels of organisation found in organisms.
1. Cell 2.Tissue 3.Organ and 4. System
(b) State the level of organisation of each of the following:
iii. Onion bulb.
i. Amoeba: cell level
ii. Hydra: tissue level
iii. Onion bulb: organ level
(c) Give TWO advantages of complex structural organisation in higher organisms.
1. specialization of body parts leading to division of labour
2. body parts work more efficiently.
3. all vital functions are carried out side by side one another without the stoppage of
4. reproduction of new members without the disintegration of the old members.
5. ability to survive in different habitat.
PART II – FLOWERING PLANTS AND SOIL SCIENCE
2. (a) State TWO modes of nutrition in plants.
1. photosynthetic 2. chemosynthetic 3. saprophytic
4. parasitic 5. symbiotic
(b) Explain what happens during light stage of photosynthesis.
ï‚§ Molecules of chlorophyll trap radiant energy of sunlight/chlorophyll absorbs
ï‚§ Energy level of chlorophyll increases/chlorophyll becomes excited/chlorophyll
ï‚§ ADP receives extra energy and become ATP/ATP is formed from ADP.
ï‚§ With the other extra energy, water molecules are split into hydrogen ions and
hydroxyl ions/photolysis of water occurs.
ï‚§ Hydrogen ions are transferred.
ï‚§ NADP accepts hydrogen ions and becomes NADPH2/NADP reduced.
ï‚§ Hydroxyl ions pass through series of chemical reactions to yield oxygen and
ï‚§ Oxygen and water are released as by-products.
(ii) Give the names of the TWO parts of the plants which aid photosynthesis.
1. Leaves 2. Stem 3. Roots
(iii) Name THREE storage structures in plants.
1. Leaf 2. Stem 3. Roots 4. Tuber/Rhizome/Corm
5. Fruit 6. Seed
3. (a) List FOUR activities of man that can lead to soil losing its fertility.
1. Continuous cropping, over cropping, mixed cropping (without replenishing the soil)
2. Deforestation, over grazing, using heavy machine.
3. Bush/crop residue burning.
4. Exposing the soil, not planting cover crop or legumes.
5. Inability to control, reduce, manage and check erosion.
(b) State FOUR characteristics of a fertile soil.
1. Adequate mineral nutrients
2. active micro-organisms
3. well drained
4. sufficiently aerated
5. enough organic matter/humus
6. good structure and texture
7. presence of earthworms
(c) Describe how erosion can be controlled in a village community.
1. Dig gutters/channels for run off after rainfall.
2. Clear drains regularly
3. Plant grass to control run off from washing away topsoil.
4. Plant shade trees to serve as wind brakes
5. Avoid indiscriminate dumping of refuse.
PART III – ANIMAL BIOLOGY
4 (a) What is balanced diet?
Balanced diet is that which contains sufficient quantities or amount or right
proportion of proteins, carbohydrates, fats and oil, vitamins, mineral salts, water (six
classes of food) to make healthy growth.
(b) State ONE role each of the following in digestion:
i. Teeth: Used for tearing or cutting, cracking or crushing and grinding or chewing of
ii. Tongue: Used to turn/mix food; roll chewed food into a ball or bolus, press food
against hard palate for swallowing and clean or clear food from the teeth
iii. Saliva: moistens food, softens food, adds water to food. Contains enzyme
(amylase/ptyalin); Digests carbohydrate/starch to maltase. The mucus in
saliva lubricates the food for easy swallowing. Saliva starts the digestion
of boiled/roasted/baked/fried carbohydrate foods.
PART IV – GENETICS AND ECOLOGY
6. (a) List FOUR components of ecosystem
1. Water 2. Air 3. Soil 4. Plants 5. Animals
6. Micro-organisms 7. Mineral salts.
(b) Explain how to measure: i. Rainfall ii. Wind direction.
1. Rain fall:
ï‚§ A rain gauge is put on a clear place in the premises. At the end of each rainfall,
the cylinder is emptied into a measuring cylinder.
ï‚§ The reading in millilitre is read and recorded.
ï‚§ The cylinder is placed back into metal container.
2. Wind direction
ï‚§ A wind vane is used in determining the direction of the wind.
ï‚§ A wind vane is installed in a convenient place.
ï‚§ It is observed anytime.
ï‚§ The arrow head of the pointer is read at the east, west, south or north as the wind
With the aid of neat sketches, show the following tools/equipment:
(i) Brick/Block laying trowel
(ii) Spirit level
(iii) Laying on trowel
A. Explain the basic differences between coarse and fine aggregates.
Coarse aggregates consist primarily of materials large enough to a proportion that cannot pass through
a standard sieve of 4.76mm radius. The maximum size of coarse aggregate is however determined by
the class of work to be carried out.
Fine aggregate is made up of materials small enough to pass through a seize of 4.76mm radius
B. Give two (2) examples of each coarse and fine aggregates
Examples of coarse aggregates include:
(i) Natural gravel
(ii) Crush stone
(iv) Sand stones
While, fine aggregates include:
(i) Natural sand
(ii) Crushed gravel
(iii) Crushed stone
A. With the aid of a line diagram, show the process of manufacture of clay bricks.
A. State four (4) precautions to be taken when laying screed to an old concrete floor.
Precautions to be taken before laying screed to an old concrete floor.
(i) Clean off the surface of the concrete floor thoroughly
(ii) Remove only laitance or scum on top of the concrete floor.
(iii) Hack the surface of the concrete to ensure good bondage either manually or mechanically
with a hack hammer.
(iv) Wet the surface with water to ensure hardening and shrinkage of screed and slab
simultaneously. This also prevents detachment of screed from the concrete base .
B. Explain briefly, the following methods of construction used for lay screed finishes.
(i) Monolithic method.
State six (6) safety regulations to be observed in the erection of tubular scaffolding.
(i) The scaffolds should be erected under the supervision of a competent personnel.
(ii) They should conform with the construction requirements as contained in the Health and
Safety work Act.
(iii) The scaffold should be strong enough to avoid accidents usually caused by their fall or
(iv) The scaffold should be rigid and fit to carry both work men and materials while in use.
(v) The standards or vertical supports upon which the load is transmitted should rest on a solid
(vi) Platforms should be closely and firmly boarded together and should be wide enough to
carry both men and materials.
(vii) The board should be provided on all platforms higher than 2m and 200mm above the top of
(viii) Guard rails should be provided on all platforms and fixed on the sides of the standards.
Heights of guard rails from top of platform should not be more than 900mm.
(ix) Ladders used for access to various platforms of the scaffold should be firmly secured at the
top and rest on a solid base or wall.
A. State four (4) advantages of pitch fibre pipes.
Advantages of pitch fibre pipes include:
(i) They are used for both domestic and trade wastes.
(ii) They are produced in portable nominal length ranges from 1.7m to 3.0m.
(iii) They also have nominal standard bores which range from 50mm to 225mm.
(iv) They are flexible in their tapered end connection
(v) They are more economical to use in bad ground conditions than clay pipes.
(vi) They can also be coupled with snap ring rubber seals to enhance longitudinal flexibility (the
expansion and contraction).
B. State four (4) advantages of flexible joints over rigid joints in drain construction.
Advantages of flexible joints over rigid joints include:
(i) Flexible joints produce the economy of expansion but rigid joints are prone to damage
under bad ground conditions.
(ii) Rigid joints are usually applied to pipes of smaller bores made mainly of clay or concrete
materials while flexible joints could be applied to both small and bigger sizes of pipes
providing additional protection to the joints.
(iii) Flexible joints when jointly used with the pipes have ability to absorb movement and
distribute the pressure uniformly over the surface area of its coverage.
(iv) Flexible joints are made of more durable materials and can withstand both thermal and
other forces exerted on them.
A. Apart from ordinary Portland cement, describe two other cements both in use and
(i) Rapid Hardening Portland Cement: This is made by mixing together chalk or limestone, with
clay or shale, heating them to a clinker and grinding them to finer powder than that for
ordinary Portland cement. The setting time is similar to that of O.P.C. But it develops
strength more rapidly. It enables form work to be struck earlier.
(ii) Extra-Rapid Hardening P.C: Manufactured by adding an accelerator e.g calcium chloride
(cacl2) to rapid hardening Portland cement. It has quick initial set. Hardening much faster
than rapid hardening p.c. It is particularly useful in cold weather. Allows concreting to
continue during low (not freezing) temperature. It is also useful for marine work in intertidal conditions.
(iii) High Alumund Cement: Made from chalk and bauxite, black in color. Develops high strength
in 24 hours, making it responsibly useful for emergency work and in cold weather. It resists
sulphate attack and some weak acids and most organic liquids.
(iv) Hydrophobic Cement: Made by adding substances to Portland cement and during the
grinding process, which form a water repellant film around each grain of cement. The
cement can thus be stored under humid and damp conditions without deterioration. During
the mixing process, the film is rubbed off and normal hydration takes place.
(v) White Cements:- By special manufacturing process and selection of raw materials, the
amount of iron in the Portland cement is considerably reduced. It is used for manufacturing
precast concrete products and in a production of cement points.
B. What is the effect of gypsum in cement and what percentage is used.
Gypsum in cement helps to retard the setting time of cement, thus allowing the work for which the
cement is required to be done before setting and hardening take place. The percentage of Gypsum used
a. With neat sketches describe dependent and independent scaffolding.
a. Define the following sewage/drainage terms:-
(iii) Half channel
(i) A manhole is an inspection chamber exceeding 900mm in depth. There are iron steps or
ladder built in the manhole wall at 300mm height to provide access into the manhole where
the depth is.
(ii) Benching is a weathering construction made at the sides of the invert of a manhole or
inspection chamber to control the flow of sewage and to allow a man to stand.
(iii) Half Channel is a pipe cut along its length either in half and used at the internal bottom of
the inspection chamber or manhole. It may also be formed with concrete.
b. Sketch a pipe showing spigot and socket ends.
A. Describe in sequence the method of rendering an old neglected wall.
The sequence is as follows:
(i) The brick joints should be raked out to form a key for the under coat
(ii) The surface of the wall should be made free of dirt and other things that will impair
(iii) Wet the surface with water
(iv) Apply rich mix mortar under coat
(v) Scratch the under coat to form key for the final coat.
B. Specify the correct mortar in external wall and internal wall surface furnishing.
For the external wall surface:
1 part of Portland cement
½ part lime; 44 ½ parts of sand by volume.
1:1:5 to 6 parts cement, lime and sand OR
1 part cement to 6 parts sand.
For Internal wall Finish:
1:0: ¼ of cement lime and sand.
C. List two advantages of rendering.
Advantages of Rendering:
(i) It prevents water penetration.
(ii) It improves appearance.
(iii) Weather proof.
Two floors are to be tiled. The size of each floor is 20m x 150mm. Allow 5% of cutting and wastage
(i) The number of tiles to be used for the whole floors and
(ii) The cost of tiles to be used if a crate of 80 tiles cost 1250.00naira.
Area to be tiled: (25m x 16m) x2= 800m2
Area of one tile: (0.2 x 0.15)m
2 = 0.03m2
No of tiles to be used = 800m2
= 26666.6 tiles= 26667 tiles
Allowance of 5% = 5/100 x 26667=1333tiles.
Total no of tiles needed = 26667+1333=28000 tiles.
(ii) The cost of 1 crate of tile =1250.000naira
1 crate contains 80tiles, therefore 28000 tiles will be contained in 28000 =350 crates
†’350 crates will cost 1250 x 350 = 437,500naira (N437,500:00)
With a scale of 1:10, draw a section through 1brick external wall showing the following in your drawing.
1. Foundation concrete
2. Footing coarse
4. Concrete slab
6. Floor screed
A. Sketch three (3) methods of fixing a door frame into a wall.
WHAT ELSE DO YOU WANT?