Which of the following is true of environmental changes?
a. they cannot be caused by human activity.
b. they may affect several populations in an ecosystem.
c. they affect food chains, but not food webs.
d. they have no effect on living organisms in an ecosystem.

You need to make 500ml of 7h9(+) media with 1x adn and 30ug/ml of the antibiotic kanamycin. your stock solutions are 10x adn and 30mg/ml of kanamycin. the solvent is distilled water. how much of each component will you need to make the desired final solution?

Liquid water turns into water vapor at which step in the water cycle

Consider darwin's first writings on the theory of natural selection. an important point of darwin's essay on the principle of population, written in 1798, was a peer's observation that in nature plants and animals produce far more offspring than can survive, this observation can be attributed to a) charles lyell. b) thomas malthus. c) jean-baptiste lamarck. d) johann friedrich meckel.