Damp soil.

He should fill a tray completely with dry soil and divide it into 2 equal part A and B. He should cover part A only with a black cloth. He should place organism Y in the middle of the tray and observe which part they move to after a while.

Curve X. The stored food in the seed leaf provides food for the seedling. Hence the mass of the seed leaf decreases as the seedling grows.

Seeds only need air, water and warmth to germinate.It would continue to develop into a seedling as it could obtain its food from the seed leaf.

It developed leaves and carried out photosynthesis.

3

Carbon dioxide. The blood at D has passed through most parts of the body and finally passed through the legs. Most of the oxygen have been used for respiration and more carbon dioxide has been produced as waste material at D than C.

3

At A the blood has passed through all parts of the body and respiration has taken place. Hence it is rich in carbon dioxide.

At B the blood has just taken in oxygen from the lungs and has not passed through the body. Hence it is rich in oxygen.

4

The seeds of fruit X has soft hair that spread out like a fan to form a wing like structure which enables the seed to be carried away a further distance.

The seeds of X are small and drier. It enables the wind carry it further.

It gives the cells a regular shape/supports the cell.

Chloroplast.

Root/Flower/Fruit. It has no chloroplast as it does not make food.

6

As vegetable A is taller it will block the sunlight and vegetable B will not be able to photosynthesize.As vegetable A grow and reproduce quickly it will compete with vegetable B for space, water and nutrients and B will eventually die as it cannot carry out its life processes.

Sally should put more floating plants in all 3 jars. She should put the most number of floating plants in Jar 1, lesser in Jar 2 and the least in Jar 3 for a fair comparison.

The animal helped to disperse the seed of the plant over a greater area./ The animal could have loosened or aerated the soil for better plant growth.

9

The plant took in water through its roots to carry out its life processes.

It prevents the evaporation of water and proves that it was the roots that took in the water.

It does not allow the moisture in the air to enter the jar and prevents the loss of moisture from the jar.

The bread would not turn mouldy as the heat would have killed the bacteria in it.

11

Container P. The coin could be seen through a greater amount of water.

11

At part A. The water is clearer and allows more sunlight to go through to enable the plants to photosynthesize.

Chloroplast

Cell Wall and Chloroplast

Increase the population of the cats as they prey on the rats.

There is an increase in the population of rats.

The seeds are dispersed further away and do not need to compete for space, water, nutrients and light.

As the seeds come out together with the dropping, they already have sufficient nutrients for better growth.

Predators of Butterfly B will think that it is Butterfly A and will not eat it as it is poisonous.

They hide themselves under the leaves.

They provide shade/shelter for the animals.

They provide oxygen through the process of photosynthesis.

They enable animals to camouflage to escape from predators.

Plant B has broad leaves. It blocks the sunlight and prevents plant A from carrying out photosynthesis to survive.

The decomposers use up the oxygen for respiration. More carbon dioxide is produced as the process of decomposition takes place.

CD

BA

Set ups A and C. All the variables are kept the same except for the roots. In Set up C the roots are wrapped in a plastic bag to make a fair test.

The leaves will change colour to become yellowish or brownish and wither.