What is fingring and who one do

Fingering is when someone uses their finger(s) or hand to stimulate their partner's vagina. Fingering is considered low-risk, safer sex, which means there's only a very small chance of spreading an infection. So fingering is a type of safer sex, but it isn't completely risk-free

Explanation:

they float because they are less dense than the water itself

something denser than water, like a rock, will sink to the bottom

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.