Question in English:
A female carries a recessive lethal gene (l) on one of her X chromosomes, and a normal dominant allele (L) on the other. What is the sex ratio to be expected in this woman's dependency if she marries a normal man?
Answer:
2/3 females
1/3 males
Explanation:
Females have two X chromosomes (XX) and males have an X and a Y chromosome (XY).
The genotype of the female is XLXl. The genotype of the male is XLY, since he is normal.
The possible genotypes are:
<u> XL Xl</u>
<u>XL</u> <em>XLXL XLXl</em>
<u>Y</u> <em>XLY </em><em>XlY</em>
<em />
All female offspring will be normal as they will always have one normal copy of the X chromosome from their father.
50% of the male offspring will be normal, but 50% will inherit the lethal gene from their mother.
Because the allele is lethal, that means XlY males will not be born.
That means 2/3 of the children will be females, and 1/3 will be males.
Answer;
B. improved ecosystem health
Explanation;
-Surface mining is a method of extracting minerals near the surface of the Earth. The three most common types of surface mining are open-pit mining, strip mining, and quarrying.
-The environmental impact of mining includes erosion, formation of sinkholes, loss of biodiversity, and contamination of soil, groundwater, and surface water by chemicals from mining processes.The environmental effects of surface mining include;
- Habitat destruction
- Soil erosion
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Air pollution from dust particulates
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Pollution (especially from sediments)
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All surface mining techniques negatively affect the environment, though some methods are more damaging than others.
Honey has more calories than sugar, so sugar is healthier
In general, the process responsible for the growth and repair of human tissue is the healing process, which takes place in three phases.
1. inflammatory response. Injured tissues release chemicals that draw resources to the area, alert the body that damage has occurred and inhibit function to prevent further injury.
2. Repair phase. Once injured area is walled off and debris removed, construction to replace or repair injured tissue begins. New blood vessels grow in the injured area maximizing transport within tissue.
3. Remodeling phase. Construction of permanent tissue , typically strong scar tissue made from dense network of collagen fibers.
Looking at it from cell level, the process of mitosis is actually taking place during healing.
Mitosis is used for growth and repair and produces diploid cells identical to each other and to the parent cell.
New cells are needed throughout life. These are for growth and replacement of damaged or worn out tissue. The body obtains such through the process of mitosis.
