Outline the evolution of monotreme, marsupial, and placental mammals.

Evolution of Monotreme: About 150 million years ago, the first monotreme have evolved. Early fossils of monotreme have been found in Australia.  A genus called steropodon is an example.

Evolution of Marsupial: About 150 million years ago, the first marsupial have evolved. A genus called sinodelphys which was about 6 inches long is an example of earliest found extinct genus.

Evolution of Placental mammals: About 110 million years ago, the earliest placental mammal have evolved. The extinct genus eomaia is an example of this. It was only 4 inches long.

his research revealed two genetically different groups of prokaryotes, which justified splitting kingdom monera into two kingdoms. the genetic and cellular differences were so great, that these two kingdoms were eventually placed into different domains in the current three-domain system.

the correct answer is sex-linked recessive.

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