What are the four main groups of carbon-based molecules?

The smallest parts of these that retain their original properties are called

Why were the results whit just water so much different than the trials with the detergent ?

Abird flies by moving its wings up and down. which two systems are most directly responsible for the movement of a bird's wings? a. skeletal and muscular systems b. respiratory and muscular systems c. skeletal and digestive systems d. respiratory and digestive systems