1.
Give reasons for the following:
Most leaves are generally flat and broad.
2. Insect-pollinated flowers have sticky pollen grains.
3. Pollen grains are dry and produced in large quantities in wind-pollinated
flowers.
4.
Seeds with damaged embryo do not germinate.
5. Seeds of wheat kept in air-tight containers do not germinate.
Please give reasons
I need them
Especially 4 , 5 and 2
Answers
1) Most leaves are flat and broad to increase the rate of gaseous exchange for the process of photosynthesis, because broader the leaves, more the surface area for the exchange of gases.
2) The insect pollinated flowers have sticky pollen grains so that these can easily stick to the bodies of the insects and can be dispersed easily.
3) Pollen grains are dry and produced in a large number in wind pollination so that they can be dispersed easily.
dry pollen grains are light weight and thus can be carried by the force of wind, besides these are produced in a large number so that, even if some of them perish, the rest can continue the species.
4) Embryo is a ball of cells formed by the process of cell division of zygote. Since embryo is the body inside the seed which actually grows into a plantlet under favorable conditions, the seeds cannot grow if embryo gets damaged.
5) Seeds of wheat are kept in air tight containers so that these do not come in contact with moisture and cannot grow further...