What is the name of this rock? (Optional: what number is it on the Moh's hardness scale?)

What is the amount of organic matter in all living organisms in a habitat called?

Which of the following is an environmental cost of agriculture? a. agronomyb. cash cropsc. pollutiond. crop rotation

All of the following are reasons why deserts extremely susceptible to wind erosion except a. they lack major root systems b. they contain thin, dry soil c. they have very few plants and trees d. they are extremely hot and lack water