As a young biologist, Charles Darwin had expected the living plants of temperate South America would resemble those of temperate Europe, but he was surprised to find that they more closely resembled the plants of tropical South America. The biological explanation for this observation is most properly associated with the field of:

Biogeography

Explanation:

Charles Darwin created a mechanism for evolution

Bio-geography is the study of how species are distributed , it helps to shows where the organisms live and why they are found in that habitat or the reason behind their absence from a certain area(geographical). This field of study show geographical distribution of organism and it provides information on the their evolution.

Charles Darwin makes used of the field by using the concept of bio-geography in relating the plants in temperate South America against the plants of tropical South America.

this headline suggests that midterm congressional   elections are at the corner and trump administration wants to activate his base by vowing to clamp down on immigrants and immigration as trump had said during his election campaign around two years ago. when a baby is born in usa, the baby becomes citizen of usa for 85 years and trump wants to end this rule of birthright citizenship to control illegal immigration and this what he said in an interview""we’re the only country in the world where a person comes in and has a baby, and the baby is essentially a citizen of the united states for 85 years, with all of those benefits,” "

the answer to your question is,

d. when a child was born.

-mabel < 3