The second law of thermodynamics states that whenever energy is converted from one form to another in a physical or chemical change, you end up with energy than before.
a. lower-quality
b. higher-quality
c. more
d. less
e. more concentrated

Which statement best describes a keystone species? o a. it has littlelmenetic variation. it has an extremely high population. 0 b. 0 c. it remains unaffected by all environmental changes. od. it has a strong influence on the ecosystem. 0 e. it's the first species to populate a new ecosystem.

Which statement describes characteristics of planarians? a they live in oceans, are parasites, and reproduce only sexually. b they live in fresh water, are parasites, and reproduce only asexually. c they live in oceans, are free living, and reproduce sexually and asexually. d they live in fresh water, are free living, and reproduce sexually and asexually.

Which line in the graph above best illustrates an effect of the carbon dioxide level in the blood on breathing rate before, during and after a period of exercise? 1.b,2.c,3.a,4.d