Which of these elements is essential to making up all organic molecules?

a. oxygen
b. hydrogen
c. carbon
d. nitrogen

The correct answer is (c) Carbon.

Organic compounds are the substance that contains carbon. The main property of carbon is catenation that make it prone to combine with the other carbon atoms. It is due to this property of carbon that a large number of organic compounds exists. The organic molecules have a very small amount of share on the surface of earth ,they are of prime importance because all the life processes are based on organic molecule. Some common examples are: Methane, Propane, Butane.

not necessarily. higher fitness requires the organism to be reproductive successful. for example, an organism at age 10 with 15 offspring is much more fit than an organism at age 15 with only 5 offspring.