Question

Give reasons : 1. Tracheids and xylem vessels are placed end to end like tubes. 2. Insect pollinated flowers produce nectar. 3. Pollen grains produced in large quantities. 4. Artificial pollination is required to produce a new variety. 5. Zygote undergoes continuous cell division. Can any one tell correct answer I have a tes​

Answer 1

Answer:

1) Tracheids and xylem vessels are placed end to end for radial conduction of water through them.

2) Nectar are the rewards that the flowering plant offers to the insect in exchange for pollinating. so nectar is produced by insect pollinated flower.

3) Pollen grains are the male gametes which need to be transferred to the female gamete for fertilization. During transfer a lot of those pollen grains are wasted or lost. So the flowers produce pollen grains in large quantities in order to have more chances of successful fertilization.

4) In natural pollination , the stigma of the flower has certain biochemical reactions to recognise the compatible pollen grain, as a result it denies any other pollen grain, so new variety cannot produce. In artificial pollination , pollen grain are artificially fertilized with the female gametes in an order to produce new variety.

5) The zygote formed after fertilization undergoes continuous cell division to further form embryo and other structures of the developmental stage. Without continuos cell division the progeny cannot form.