BIOLOGY 2 Marks Questions

The photosystem I keeps on removing electrons from photosystem II. A continuous supply of electrons is required to further carry on the reaction. When water molecule is split, electrons are released. These electrons maintain the continuous supply from photosystem II to photosystem I. oxygen is also released after splitting of water, which helps in maintaining the balance of oxygen in the environment.

Every organism which is born on this earth has some role with respect to another organism, ecosystem and biospheres existing on earth. After performing its functional part in its life cycle it contributes to the cycle of nature and dies. This way natural control on all natural process is maintained. This is why the death of the organism is inevitable.

Functions of Thymosins. Thymosins play a major role in the differentiation of T-lymphocytes, which provide cell mediated immunity. In addition, thymosins also promote production of antibodies to provide humoral immunity.

Bidder's canal is present in the kidney of a frog. It communicates with the ureter, which leaves the kidney near its end and opens into the cloaca.

Presence or absence of hair on the epidermis will give the clue. Those with hair are slides of root. Cuticles will be present on the slide of stem.