Which activity takes place because of the contra O fertilization
O cell differentiation
Which activity takes place because of the controlled timing of gene expression

The that takes place because of the controlled timing of gene expression is cell differentiation. It is the process by which a less specialized cell becomes a more specialized cell type

hence ans is differentiation

the correct answer is option b

behavioral response need communication and thus co-ordination at several levels such as interaction among cells, organ system and the entire organism.

behavioral response produces both internal and environmental stimulus.

bal is blood alcohol level. bac will normally be higher in a person with more body fat. so the answer to your question would be, as body fat decreases, the increasing rate of bal decreases.