Sexual facts & stats

Question 1

The oldest known evidence of sexual reproduction in flowering plants comes from fossil flowers about how old?

Accepted Answer

about 100 million years old. These Cretaceous-period fossil flowers document some of the earliest known flowering-plant reproduction.

Question 2

Insects, most of which reproduce sexually, make up roughly what share of all known animal species?

Accepted Answer

more than two-thirds. Insects are by far the most numerous group of animals on Earth, and nearly all reproduce sexually.

Question 3

Living mammals fall into three groups that all use internal fertilization: monotremes, marsupials and which third group?

Accepted Answer

placentals. Placental mammals, which include humans, are the largest of the three mammal groups.

Question 4

Some arthropod species can reproduce without mating at all, through a process called what?

Accepted Answer

parthenogenesis. In this process, females can produce offspring from unfertilized eggs, though most arthropods still rely on sexual reproduction.

The basics