Assertion: The earliest organisms that appeared on the Earth were non-green and presumably anaerobes.
Reason: The first autotrophic organisms were the chemoautotrophs that never released oxygen.

If both assertion and reason are true and reason is the correct explanation of assertion

If both assertion and reason are true but reason is not the correct explanation of assertion

If assertion is true but reason is false

If both assertion and reason are false.

Solution

If both assertion and reason are true but reason is not the correct explanation of assertion

The first living organisms originated among organic molecules and in oxygen free atmosphere. They presumably obtained energy by fermentation of some of these organic molecules. They were non-green and anaerobes (capable of respiring in absence of oxygen). They depended on the existing organic molecules for their nutrition, hence they were heterotrophs.

Then came autotrophs when the supply of existing organic molecules were exhausted. These organisms were capable of producing their own organic molecules by chemosynthesis. They synthesized food from inorganic molecules. Photoautotrophs were also anaerobic at first but later on oxygen releasing photosynthetic organism developed

Some More Questions From Evolution Chapter

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Evolution

Some More Questions From Evolution Chapter

What are the two key concepts of Darwinian Theory of Evolution

What were the units of life according to the early Greek thinkers ?

Mention the type of nutrition in the cells originated first during the origin of life.

Which group of organisms were responsible for appearance of free oxygen in the atmosphere of the primitive earth ?

What is meant by the term fossil ?

What is the type of evolution in which the same structure developed along different directions due to adaptations to different needs ?

Name the different eras of geologic time scale.

What is single step large mutation?

Consider a thorn in Bougainvillea and a tendril in cucurbita. Are these two organs homologous or analogous ? Give reason.

Give two examples that represent adaptive radiation.

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