When you look at the night sky, sometimes there is a full moon and sometimes the moon looks like it’s barely there. why does this happen?

This happens because there are several moon phases that occur over a month. Such as the new moon, first quarter, full moon, last quarter, etc. This changes the view of the moon from its' angle.

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.