22.
Photosystem I (PS-I) and Photosystem-II (PS-II) are named

24.
In some bisexual flowers where the stigma and anthers mature at the same time, self-pollination is avoided by some sort of barrier. This condition is known as

25.
The process by which the humus derived from the dead organic matter gets mixed in the upper layers of the soil which becomes dark coloured, is known as