Which of the following is an endothermic reaction?

a. burning wood
b. an explosion
c. burning a match
d. the cooling of an ice pack

Does the energy in a solid increase or decrease when changing to a liquid?

Describe the difference between a. a hypothesis and a theory and b. an observation and an experiment.

An animal cell loses the ability to convert energy stored in food to energy that the cell can use. which of the cell's organelles has stopped working? a. the mitochondria b. the nucleus c. the vacuoles d. the endoplasmic reticulum