What is the cause of the “red tide”?
a large oil or gasoline spill gives the water its reddish color
the blood from fish or other marine animal in a massive “die-off”
a sudden growth spurt or “bloom” in algae
a toxic condition of the water cause by beach pollution

In the practice of science, this type of reasoning is used to develop explanations.

What's wrong with this ecological pyramid? (multiple choice)1. secondary consumers should be at the bottom of the pyramid2. the sun has an arrow leading to decomposers 3. primary consumers should come after the sun4. energy retained should increase from the bottom to the top5. the sun should be at the bottom of the pyramid

Natural selection changes allele frequencies because some survive and reproduce more successfully than others.