Q: What was the first mass extinction that occurred on earth? Choices: - late Devonian mass extinction - paleozoic mass extinction - proterozoic mass extinction - precambrian mass extinction A:
precambrian mass extinction

(Question)
Q: In science, what can be described as a set of steps that help us to answer questions? Choices: - theory - hypothesis - scientific controls - scientific method A:
(Answer)
scientific method

Ques: Q: When electrons return to a lower energy level, they emit the excess energy in the form of what? Choices: - weight - electricity - energy - light A:
Ans: light

(Q).
Q: Birds have light-weight bones that are filled with what? Choices: - water - proteins - blood - air A:
(A).
air

Ques:Q: Behaviors that occur naturally and are not learned are called what? Choices: - adaptive - intuitive - acquired - innate A:

Ans:innate

Question: Q: What kind of anaerobe is yeast? Choices: - mutualistic - obligate - aerobic - facultative A:
Answer:
facultative