In our solar system, gas giants are much bigger than terrestrial planets, and they have thick atmospheres full of hydrogen and helium. On Jupiter and Saturn, hydrogen and helium make up most of the planet, while on Uranus and Neptune, the elements make up just the outer envelope.
It boosts ecosystem productivity where each species no matter how small have a role to play
<span>D. can grow as the animal grows. Endoskeleton is an internal skeletal system that provides a framework for the body. Unlike an exoskeleton, it grows as the body grows. </span>Humans, birds, fish and mammals have endoskeletons.