The answer is letter C. fertilization.
Meiosis reduces the chromosome number from diploid (2n) to haploid (n).
<span>During fertilization like that of human somatic cells which has 46 number of diploid chromosomes, a haploid sperm cell and a haploid egg cell combine to form a diploid zygote. Each parent contributes 23 number of chromosomes to the offspring which makes the total of 46 chromosomes. Since meiosis halves the chromosome number but the diploid condition is restored during fertilization</span>
Answer:
The correct answer is option A
Explanation:
Hypoparaghyroidism occurs when thyroid gland produce little parathyroid hormone.
This is caused by:
1. Injury to the parathyroid glands during thyroid and neck surgery.
2. It is also caused by auto immune disorder. This is as a result when the body's natural defence against invading organisms starts to attack perfectly healthy tissues.
3. Congenital defects: This is as a result when infants are born without parathyroid tissue, that is ability to make thyroid glands or when the mother has hypoparathyroidism.
Answer:
The right answe is C.
Explanation:
The limit to how large any given population could be is defined by the concept of " carrying capacity". It refers to the fact that in nature populations grow much faster than resources do, and this impose a limit to population sizes (if there is no enough nutrition sources, the number of individual can not go up).
<u>Answer:</u>
In ecology, catastrophes permanently alter the physical structure of the existing environment.
<u>Explanation:</u>
- The ecological disturbances include flood, strom, plague, fires, earthquakes, tsunami, volcanic eruptions, climatic change and impact of humans on the environment like deforestation ,nuclear testing etc.
- These factors can have a visible impact on the structure of the earth and permanently alter the environment.
- The visible effects of these disturbances are global warming, extinction of selective species, change in the course of rivers, submergence of coastal areas, sudden movement of the tectonic plates and formation of sudden cracks on the earth's crust.
