The letter that represents enzyme is B.
Answer:
organizational effect.
Explanation:
Organizational effect is a long-term effect of hormonal action typically occurring in fetal development or the early postnatal period that leads to permanent changes in behavior and neural functioning. For example, the presence of testosterone in young male rats leads to long-term male-typical behavior, and female rats can be masculinized by neonatal exposure to testosterone.
Organizational effects act during development, often during critical period. Such hormones affect the construction or fine-tuning of sex organs or neural circuits underlying behavioral capacities that will be needed in adulthood.
Organizational effects are often under tight genetic control, and not subject to major influence by environment.
Organizational effects are often irreversible.
This is because not all genes are expressed at the same time, so not all the proteins are present at a certain moment. The mechanisms that cell uses to control gene expression are called regulation of the gene expression. Thanks to regulation of the genes, cells have the ability to increase or decrease the production of specific gene products such as proteins. This property is important for the adaptability of an organism because it allows the cell to express protein when needed.
The author assumes that the question can be answered by applying principles of anatomy, physics and evolutionary biology. First reason he suggests is that cats are small and they have a favourable mass-surface area ratio. Next, he suggests that cats have soft tissues that absorb the shock and they land on all four limbs, dividing the shock. This is because of their body shape and its centre of gravity. He says that felines have this kind of body structure (that canines lack) because years of falling from trees etc. has evolved their body in this way.