What contains dozens of carcinogens

What claim did thorne make? what evidence supported his claim?

The eruption of a nearby volcano causes a prairie ecosystem to receive a lot less sunlight. which of these is the most likely effect on the ecosystem? a-an increase in biodiversity. b-an increase in immigration to the area. c-a decrease in available water. d-a decrease in plant growth.

An easy way to calculate the amount of energy available at each level is to what?