Which statement does not describe geographic isolation? a. members of a species are cut off or separated from the rest of its species. b. build up of traits over time. c. separation by rivers, volcanic activity, or mountain ranges. d. a new species forms because a group cannot mate with original members of a species.

D. A new species forms because a group cannot mate with original members of a species.

Explanation

Geographical isolation deals with a plant, animal or organisms being separated and unable to exchange genetic material with other organisms of the same species. This can be caused by accident or coincidence.

Water bodies, mountains are sometimes responsible for the isolation as the animals may decide to migrate to other parts of the environment and become separated from the main species.

A new species forming because a group can’t mate with the original species is a false example of geographic isolation because there is no geographic barrier or proof of separation.

step 1: nitrogen fixation- conversion of atmospheric no₂ into forms useful to plants by lightning, bacteria, and cyanobacteria.

step 2: nitrification-process of converting ammonia to nitrite or nitrate.

step 3: assimilation-plant roots absorb new form of nitrogen.

step 4: ammonification-conversion of organic nitrogen to ammonia by bacteria involved in decomposition.

step 5: denitrification-bacteria turns the decomposed matter back into n₂o, which is released into atmosphere; repeat cycle.