Which of the following cycles does not involve living organisms?
a. carbon cycle
b. oxygen cycle
c. rock cycle
d. nitrogen cycle

Which best describes the digestive system of arthropods? a incomplete, two openings b complete, one opening c two-way, one opening d one-way, two openings

Which of the following is the source of energy for photosynthesis? a.) glucose b.) chlorophyll c.) carbon dioxide d.) sunlight

Explain how the political influence of african americans leaders became weaker.