Class mammalia is divided into two subgroups: marsupials and placental mammals.
a. true
b. false

The given statement is false.

Explanation:

The mammals can be differentiated into three main groups on the basis of the development of their babies. These three groups are marsupials, monotremes, and placental mammals, which is the largest group. The monotremes refer to the mammals, which lay eggs. The marsupials refer to the mammals, which give birth to young ones that are not developed completely. While in a placental mammal, the development takes place within the body of a mother until and unless its systems of the body start to work on their own.

during the process of dna replication, brdu can replace thymidine and incorporate into the newly synthesized dna, cell proliferation thus can be reflected in the extent of brdu incorporation.

some fungi obtain their nutrients from a living host (plant or animal) and are called most biotrophic fungi have fairly narrow host ranges—they are specialized on a limited called rhizomorphs that allow the fungus to grow from one tree to another. ascospores are formed inside a sac-like structure called an ascus. so your answer is a