Question

Various life forms appeared on earth at certain time periods in the history of several million years. Arrange the following in the order of their appearance on earth (starting with the earliest)
1. Multicellular organisms
2. Eukaryotes
3. Organisms with an exoskeleton
4. Angiosperms

A)1,2,4,3
B)1,3,2,4
C)2,1,4,3
D)2,1,3,4

Answer 1

Life began on the earth at least 3.5-4 billion years ago. This is due to the evolution after which many different varieties of organisms appear on the earth.

Complete answer:
The single-celled microorganisms were the first living things on the earth. They lack a nucleus or cell membrane and are called prokaryotes. This happened around 4 billion years ago. There are many theories developed on the evolution of life after studying the fossils and the relationship between the organisms.

Option A: The first organisms on the earth were single-celled i.e. prokaryotes and eukaryotes. After which multicellular organisms developed. Multicellular were not the first organisms. Therefore this is an incorrect option.

Option B: The first organisms on the earth were single-celled organisms i.e. prokaryotes and eukaryotes. After which multicellular organisms developed. Multicellular were not the first organisms. Also, the organisms with exoskeleton developed after a long time. Therefore this is an incorrect option.

Option C: The first organisms were single-celled prokaryotes after which single-celled eukaryotes developed i.e. cells with a nucleus. These single-celled organisms then became multicellular and started to diversify. After this, the organisms with exoskeleton developed not angiosperms. Therefore this is an incorrect option.

Option D: After eukaryotes developed they became multicellular and started to diversify. After this, the organisms with the exoskeleton and then the multicellular angiosperms developed which had tissue level of organization. Therefore this is the correct option.

Hence, the correct answer is option (D)

Note: Evolution is defined as the process by which various organisms have been believed to develop from earlier form over millions of years. Origin of life means the appearance of first life from non-living organisms and evolution of life means the formation of complex organisms from simple organisms.