Diatoms have cell walls composed of silicon dioxide.
A. silicon dioxide.
your answer is A because a geometric progression is increased by a factor of 3, therefore 4x3=12 and 12x3=36.
hope this helps!!
Answer:
The coral reefs of the Caribbean are thought to be under threat
Explanation:
Overfishing threatens over 60 percent of Caribbean coral reefs. Declines in coral cover and increases in algal cover have been observed across the region. This analysis identified about one-third of Caribbean reefs at high threat from overfishing pressure and about 30 percent at medium threat.
