Anything that relates to sexual reproduction (gametes coming together to fertilize) should be crossed off.
Not much context was provided but you can look back to some other questions I've answered, I have a full in-depth answer to the same question another person had.
Answer:
the sun or grass
Explanation:
first the sun because the sun helps produce photosynthesis which grows the grass so that other animals can eat from the grass
Various hormones have various functions. which hormone are you interested in?
Answer: By Hormonal action and Nervous coordination
Explanation:
Hormones are substances produced by one tissue and conveyed by the bloodstream to another to effect physiological activity. Homeostasis is the maintenance of a stable internal environment in the body.
Body systems such as digestive, circulatory, excretory systems etc, all are coordinated to achieve a STABLE INTERNAL ENVIRONMENT by the aid of HORMONES AND/OR NERVOUS COORDINATION.
For Example: the vasodilation of blood vessels during hot weather, and the opposite action of vasoconstriction during cold weather are both controlled by Hormonal action and nervous coordination which leads to a stable body temperature preventing excess heat accumulation.
Also, Nervous system controls the body systems, such that the muscle contractions are joined to actions like sweating, breathing, respiration etc
So, to maintain homeostasis hormonal action and Nervous coordination is necessary.
The aspect of his experimental process which is most important for obtaining reliable results is repeating his data collection many times.