All of the options are correct except B.
Rapid descent is imperative as the condition can<span> be fatal.</span>
A compound forms whenever two or more atoms form chemical bonds with each other. The chemical formula for water is H2O, which means each molecule of water consists of one oxygen atom chemically bonded to two hydrogen atoms. Thus, water is a compound.
The answer is c. Natural selection is when inheritable traits that they need to survive is passed down to the next generation. Biological revolution changes the environment so the organism's offspring has to change with it through genetic variations. If you increase it's life span than you may not have genetic variation over a period of time.
