Which type of organic molecule is wax?
a. carbohydrate
b. protein
c. nucleic acid
d. lipid

Wax is a simple form of lipid molecule. It consists of a long-chain of alcohol and a fatty acid. Many of the natural occurring wax found in nature are used as ingredients for products found in stores like ointments, hand cream, and cosmetics.

Plants have naturally occurring wax on their leaves and stems; these serve as coatings to prevent them from losing excess water. Other forms of wax found in nature are beeswax, used by bees to make their cones for honey and eggs; sperm whales have spermaceti wax found in their blubber; and carnuba wax, is an ingredient commonly used for car waxes, commonly found in Brazilian palm trees. 

Where's the picture of the model?