Question

Choose the correct answers from the alternatives given .
The best evidence for a common origin of all life is

• A. Comparative anatomy
• B. Comparative embryology
• C. Biogeography
• D. Molecular biology

Answer 1

The correct option is D Molecular biology

Similarities between biological molecules can reflect shared evolutionary ancestry. At the most basic level, all living organisms share:

• The same genetic material (DNA)
  
• The same, or highly similar, genetic codes
  
• The same basic process of gene expression (transcription and translation)
  
• The same molecular building blocks, such as amino acids.
  

These shared features suggest that all living things are descended from a common ancestor and that this ancestor had DNA as its genetic material, used the genetic code, and expressed its genes by transcription and translation. Present-day organisms all share these features because they were "inherited" from the ancestor (and because any big changes in this basic machinery would have broken the basic functionality of cells). These molecules are the best evidence of a common origin of life.

So, the correct option is 'Molecular biology'.