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rusak2 [61]
3 years ago
13

Given what you know about the selective pressures associated with malaria and sickle-cell anemia in the tropical areas of sub-Sa

haran Africa, is there evidence of selection operating in this population? If so, which genotype appears to be favored? Explain.
Biology
1 answer:
julsineya [31]3 years ago
8 0

Answer

HBA HBs

Explanation:

In some parts of Africa, up to 20% of the population are carriers of the sickle cell gene. This suggests that the trait must have a survival value. The carriers of the trait have a much lower susceptibility to malaria than normal individuals. This is because the malaria parasite survives very poorly in sickled red blood cells.

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List and describe the most important erosional and depositional features of a river and how these features form.
Mkey [24]

Answer:

Meanders

As the river makes its way to the middle course, it gains more water and therefore more energy, so material can be carried in suspension and is used to erode the river banks. Lateral erosion starts to widen the river. When a river flows over flatter land it develops large bends called meanders.

As a river goes around a bend, most of the water is pushed towards the outside. This causes increased speed due to less friction and therefore increased erosion (through hydraulic action and abrasion).

The lateral erosion on the outside bend causes undercutting of the river bank to form a river cliff.

There is less water on the inside bend of a meander so friction causes the water to slow down, lose energy and deposit the material the river is carrying, creating a gentle slope.

The build-up of deposited sediment is known as a slip-off slope (or sometimes river beach).

The fast current on the outside bank causes lateral erosion, creating a river cliff. The slow current on the inside bank causes deposition, creaitng a slip-off slope.

Oxbow lakes

Due to erosion on the outside of a bend and deposition on the inside, the shape of a meander will change over a period of time. Erosion narrows the neck of the land within the meander and as the process continues, the meanders move closer together. When there is a very high discharge (usually during a flood), the river cuts across the neck, taking a new, straighter and shorter route. Deposition will occur to cut off the original meander, leaving a horseshoe-shaped oxbow lake.

Erosion makes the neck narrow. During floods, the river takes the shortest course through the neck. The river has a new straighter course and the abandoned meander is called an oxbow lake.

Explanation:

3 0
3 years ago
Explain how water makes its way to the leaves in the tops of the tallest trees against the force of gravity. Name what the climb
mart [117]

Answer: Capillary action occurs because water is sticky, thanks to the forces of cohesion (water molecules like to stay close together) and adhesion (water molecules are attracted and stick to other substances).

It reminds me of naruto

3 0
3 years ago
What is microbiology?
Gre4nikov [31]
<span>the part of science that deals with microorganisms</span>
5 0
3 years ago
Read 2 more answers
O recall how gas exchange occurs in<br>some water organisms,​
Lubov Fominskaja [6]
In aquatic plants, water passes among the tissues and provides the medium for gas exchange. In terrestrial plants, air enters the tissues, and the gases diffuse into the moisture bathing the internal cells.

Hope this helps
3 0
3 years ago
The causative agent for PAM, a rare but severe brain infection, was found to be Naegleria, an amoeboid protozoan living in warm
Tju [1.3M]
The answer is letter B. <span>Sporozoa, because it is a disease-causing protozoan
</span>
Sporozoa is a large phylum of parasitic protists that are responsible for many forms of infections, one of which includes PAM.

<span>Thank you for posting your question. I hope you found what you were after. Please feel free to ask me more.</span>



4 0
3 years ago
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