Individuals who are heterozygous for the sickle-cell allele suffer less from the attack of malaria because a small percentage of the red blood cells are sickle-shaped. They are more resistant to malaria than individuals who have two copies of the normal haemoglobin allele. Heterozygous individuals have a better chance of surviving and reproducing in regions where malaria is prevalent since they do not fully contract the disease.
A direct linear function
A direct relationship is linear b/c they go in a straight line.
Answer: I believe this is FALSE.
Explanation: I say this because, although photosynthesis is required to keep the plants alive which causes respiration. It is not objectively needed in the cycle, and it isn't caused by animals.
I hope this helps :D.