Answer:
See the answer below
Explanation:
Anthers release pollen, which lands on the stigma of another flower of the same species. The pollen grain produces a pollen tube that grows down the style, to the ovary, and into the ovule. The sperm cell fertilizes the egg cell. The ovule develops into the seed, and the ovary becomes the fruit.
<em>During fertilization in plants, the anther which carries pollen releases pollen grains. Once the pollen lands on the stigma of a flower of the same species, it germinates. The pollen grain produces a pollen tube that grows through the style of the stigma down to the ovary and into the ovule. One of the sperm cells fuses with the egg cell of the ovule to form the zygote while the other sperm cell fuses with the polar nuclei to form the endosperm in a process known as double fertilization. After fertilization, the fertilized ovule becomes the seed and the ovary becomes the fruit. </em>
There are several costs associated with using wind turbines to generate electricity.
<u>Explanation:</u>
Using wind turbines to generate electricity comes with the cost of installation of the turbines. A suitable site for installation has to be selected and windmills of the required height are installed. Cost of maintenance is another cost associated with the usage of wind turbines.
The windmills are subjected to several environmental factors like rainfall, sunlight etc. These can cause damage to the windmills. Thus a regular maintenance of the turbines is essential.
Cost of procuring appropriate land for installation of wind turbines is another associated cost. Locations apt for harnessing wind energy are limited. Moreover the windmills have to be set up across a large area to produce energy in a decent scale.
Answer:
A. Molecular changes such as extracellular signals on extracellular ligands can result in quick changes in cell behaviour. One example is insulin. Upon insulin binding on the receptor on the cell membrane, the cell release GLUT4 transporters (for muscle cells) to increase uptake of glucose.
B. Slow changes in cell behaviour can be observed for other lipophilic hormones or intracellular receptors such as glucocoortoid or estrogen which reacts with receptors in the cells.
C. Insulin is required to maintain a constant blood glucose level and hence levels of insulin has to be mediated in correspondence to the blood glucose levels. Fast acting signalling is thus required for homeostasis of blood glucose levels. Where for such lipophilic hormones such as steriods, glucocortoid, these hormones tend to have a longer lasting effect and hence results in a slow change.
