For which of these questions could a testable hypothesis be developed? Check all that apply. A. Do children’s heart rates increase at the same speed when walking uphill?
B. Is experimenting with moldy bread more fun than experimenting with yogurt cultures?
C. Does temperature affect how long blood can be stored?
D. How does moisture affect the growth of moss on a tree?
E. Which of Leeuwenhoek’s microscopes was the coolest?

c.

explanation:

3 1/4 %

explanation:

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.