Hey pizzalover! The answer from this question would be
a. oxygen
Hope it helps
A) A textbook definition would be that genetic drift is: a random change in allele frequency caused by a series of chance occurences that cause an allele to become more or less common in a population. In layman's terms, this means that genetic drift happens when luck makes the genetic pool of the population to deviate from what is expected.
B) The cause for this genetic drift is the aformentioned couple. Because amish communities are small and they select partners from their community, having even a couple of carriers of alleles in a community can make the allele freuency much larger than expected; for example, if the community was 100 persons, the percentage would be in the order of 1%, still much larger than the general population. Thus, the cause here is that a small population had a couple of carriers.
C) Sexual reproduction leads to a mixing of alleles from both mother and father and helps diversity. When a population is isolated, the gene pool is fixed and no new genes can come in, reducing diversity. Also some people that have an allele might die, hitting diversity even more. Finally, having a small population creates a strong pressure in some circumstances that leads to elimination of some traits and diversity.
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<h3>⇝ <u>Epidermis</u> :</h3>
Protective tissues includes epidermis & cork. Epidermis is basically a simple permanent tissue, protective in function. It forms one-cell-thick covering over all the parts of plant.
<h3>⇝ <u>Characteristics of Epidermis</u> : </h3>
- Epidermis is formed of living cells, arranged in a single layer.
- In aerial parts, epidermis is covered with a waterproof and noncellular waxy covering called cuticle.
- Cells form a continuous layer, but in leaves epidermis has small openings called stomata.
- Each stoma is guarded by a pair of bean-shaped guard cells which govern opening & closing of stomatal aperture.
<h3>⇝ <u>Functions of Epidermis</u> :</h3>
- Epidermis protects the underlying tissues from mechanical injury, chemicals & infection.
- Cuticle of epidermis protects against water loss & desiccation. It checks the rate of transpiration & evaporation and prevents wilting.
- Stomata in the epidermis of leaves help in gaseous exchange during respiration & photosynthesis.
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