Answer:
The correct answer will be-
1. Homologous recombination- crossing over
2. Occur-during pachytene of meiosis I of gamete formation.
Explanation:
The basis of diversity of organism present on earth lies in the sexual mode of reproduction possessed by the organism to produce offspring. The sex cells involved in the reproduction are formed by a process called meiosis.
During the formation of gametes, at the pachytene stage of meiosis I take place a mechanistically conserved process which leads to the exchange of DNA segment between non-sister chromatids called crossing over through a process known as homologous recombination.
This exchange of genetic material in the homologous chromosomes increase the genetic diversity of the organism on the earth.
Answer:
Stem cells cut and repair their own DNA to promote formation of new tissues.
Explanation:
Stem cells cut itself and then repair their own DNA as a mechanism of activating genes that promote the development of new tissues. Stem cells are special type of cells that the ability to develop into many different types of cell such as muscle cells, brain cells etc. These cells are also capable to repair damaged tissues in the body.
At least 75% of the history of the earth
