Regarding assertion and reason, select the right option.
Assertion (A): Pollen grains have a tough outer covering.
Reason (R): Pollen grains differs in size, shape, colour and design.
Regarding assertion and reason, select the right option.
Assertion (A): Pollen grains have a tough outer covering.
Reason (R): Pollen grains differs in size, shape, colour and design.
The correct option is B Both A and R are correct and R does not explain A
The wall of pollen grain is divided into two layers - the outer exine and the inner intine. The outer exine can be further differentiated into two layers ektexine and endexine. And the ektexine is then further divided into three layers viz., an inner foot layer, a middle bacula and an outer tectum. Pollen grains differ from each other in size, shape, colour and designs. The layers responsible for this disparity are the tectum and bacula which form designs over the surface of pollen grain. Pollen grains do possess a tough covering but this is in order to protect and ensure the viability of the male gametes they carry.
Both A and R are correct and R does not explain A
The wall of pollen grain is divided into two layers - the outer exine and the inner intine. The outer exine can be further differentiated into two layers ektexine and endexine. And the ektexine is then further divided into three layers viz., an inner foot layer, a middle bacula and an outer tectum. Pollen grains differ from each other in size, shape, colour and designs. The layers responsible for this disparity are the tectum and bacula which form designs over the surface of pollen grain. Pollen grains do possess a tough covering but this is in order to protect and ensure the viability of the male gametes they carry.
