How do gravity and inertia work together in our solar system?

They work together to keep things in orbit.

Explanation:

Gravity pulls things in, while inertia says that all celestial objects will try their best to continue forward. The results in the orbiting of celestial objects, like the Earth, around other celestial objects, like the Sun.

(Source: sciencing.com)

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.