How does fire helps matter cycle through the biotic and abiotic parts of an ecosystem

What is usually (but not always) related to the metabolic processes of living organisms in its organic form?

Which of the following statements is true about the relationship between genetic variation and natural selection? a. genetic variation must be present in a population before natural selection can act on it. b. genetic variation arises in a population as a result of natural selection. c. natural selection can act on a population whether there is genetic variation within the population or not. d. after natural selection acts on a population, the amount of genetic variation in the population always increases.

Do plant cells perform cellular respiration?