1) Which of the following geologic time periods is associated with the birth of the Earth and the first appearance of the earliest life forms?
A. Cenozoic
B. Mesozoic
C. Paleozoic
D. Precambrian
A. Cenozoic
B. Mesozoic
C. Paleozoic
D. Precambrian
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Cenozoic - Mammals become the dominant form of vertebrate life on land, as flowering plants do likewise over their closest relatives. Insects are the most abundant of all animals (and may well have been before this time).
Mesozoic - dinosaurs are the dominant form of animal life on land, with close relatives in the oceans and the air; mammals evolve from reptile ancestors, as do birds from dinosaurs, and flowering plants appear near the end of this time.
Paleozoic - multicellular life expands into a much wider variety of forms than existed at the end of the Precambrian, including invertebrates and vertebrates; life moves in greater variety from the oceans to the land.
Precambrian (an informal name for the time before the Paleozoic) - early on the planet Earth formed [about 4.5 billion years ago]; life first appeared in the fossil record around 4 billion years ago, but remained single-celled in nature until the latest Precambrian, roughly 600 million years ago.
Mesozoic - dinosaurs are the dominant form of animal life on land, with close relatives in the oceans and the air; mammals evolve from reptile ancestors, as do birds from dinosaurs, and flowering plants appear near the end of this time.
Paleozoic - multicellular life expands into a much wider variety of forms than existed at the end of the Precambrian, including invertebrates and vertebrates; life moves in greater variety from the oceans to the land.
Precambrian (an informal name for the time before the Paleozoic) - early on the planet Earth formed [about 4.5 billion years ago]; life first appeared in the fossil record around 4 billion years ago, but remained single-celled in nature until the latest Precambrian, roughly 600 million years ago.
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A. Cenozoic - 1st humans
B. Mesozoic - 1st Dinosaurs
C. Paleozoic - 1st vertebrate land animal
EDIT:
I will submit to other answers.
B. Mesozoic - 1st Dinosaurs
C. Paleozoic - 1st vertebrate land animal
EDIT:
I will submit to other answers.