<u>Answer:</u>
<em>Double fertilization is a significant feature in angiosperms or flowering plants.
</em>
<u>Explanation:</u>
The pollen grains carrying the sperm cells from a flower land on the stigma which is a <em>component of the female reproductive part of a flower.</em> The pollen grain contains the sperms and once the pollen lands on the stigma it grows pollen tub into the ovary through the style which is a tube connecting<em> stigma to ovary. </em>
Ovary contains ovule which contains egg cell as well as two polar nuclei and all these are haploid. The sperm in the pollen is also haploid. On the release of two sperm cells, one sperm fuses with the egg cell and the other sperm fuses with the two polar nuclei which results in the <em>formation of a diploid zygote</em> which is diploid and a triploid cell.
The diploid zygote develops into the embryo after cell division and the triploid cell develops into endosperm that provides nourishment to the embryo. Thus double fertilization becomes <em>significant in flowering plants.
</em>
Answer:
the male part of a flower is called the stamen, it consists of a long slender stalk, the filament, with a two-lobed anther at the tip.
the female part of a flower is called the pistil, it consists of the stigma, the style, the overy and the ovule.
Answer:
When you run, your muscles use energy and contract. This contraction and use of muscle fibers produces heat, lactic acid, and carbon dioxide. Your body will attempt to correct homeostasis by sweating to cool down your body (When the water in your sweat evaporates, it takes some heat energy with it), you breath harder to get rid of the excess carbon dioxide, and your blood attempts to clear the lactic out of your muscles.
Daughters get one X gene from each parent.
If the father is a normal male, he carries only a normal X-gene.
Therefore the daughter will always get a normal gene from the father, and a 50% probability getting an affected gene from the mother, therefore 50% chance of becoming a carrier. The other 50% she will inherit a normal X-gene from each parent, thus a healthy female.
In conclusion, no daughter will have haemophilia from a carrier mother and a normal male.
(however, sons will have a 50% chance of inheriting affected X-gene and hence will have haemophilia).
A population of squirrels is preyed on by small hawks at maturity. the smaller adult squirrels can escape into burrows. the larger adult squirrels can fight off the hawks. after several generations, the squirrels in the area tend to be very small or very large. this is an example of disruptive selection. In disruptive selection, the extreme traits i.e., very small and very large sizes are favoured over intermediate trait i.e., average size.
