Which phase of the cell cycle would you predict would be disrupted the most by this chemical?

During the S phase the cell replicates the chromosomes by taking one chromatid and effectively doubling it (these are later ripped apart during Anaphase in Mitosis). So during the S phase of the Interphase cycle, chromosomes are replicated into two sister chromatids.

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.

this is a good question! i'll do some research and come back when i have the answer!