The complicated molecules that make up living things usually contain carbon. why is carbon so important in these molecules?
a. carbon can form four strong covalent bonds.
b. carbon can only form one bond at a time.
c. carbon forms ionic bonds with most elements.
d. carbon is the lightest and smallest element.

A
The strong, stable and high number of bonds that carbon can form make it an essential element in organic molecules. 

Glucose, also called grape sugar, blood sugar or corn sugar, is among the simplest and one of the primary naturally occurring sugars. produced naturally by plants as the primary photosynthesis product, it is heavily used by living beings as a main energy source and is necessary for cellular respiration. chemically, it is a monosaccharide carbohydrate and serves as a building block for complex sugars like starch.