What is true of mass extinctions?
a all life on earth dies when a mass extinction happens
b in each mass extinction, over 50% of animal species died.
c mass extinctions happen frequently.
d there is no evidence for past mass extinctions.

Which is the correct order in the scientific process? ask a question ® form a hypothesis ® make an observation ask a question ® make an observation ® form a hypothesis make an observation ® form a hypothesis ® ask a question make an observation ® ask a question ® form a hypothesis

Which statement describes a way in which the digestive and excretory systems work together? a. the nephrons absorb nutrients from food going to the large intestine. b. the excretory system balances blood gases in the small intestine. c. the intestinal villi filter blood and send wastes to the bladder. d. the excretory system balances the salts and water obtained from digested food

Alexa is preparing for a presentation by creating note cards identifying keywords that describe various features of each type of plate boundary. which words apply to all three of the convergent boundaries?