Which statement is most true about a hypothesis?
a .it is a conclusion drawn in an investigation.
b. it is an observation that you make.
c. it is a trend observed in data.
d. it is a testable solution to a question.

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