Answer:
True
Explanation:
During meiotic division involved in the formation of the gametes in organisms. The meiotic division reduces the number of chromosomes by half during gamete formation.
In the given question, Horse contains 32 pairs of chromosomes or 64 chromosomes and the donkey contains 31 pairs of chromosomes or 62 chromosomes.
The gametes of a horse through meiotic division will contain 32 chromosomes and gametes of a donkey through meiotic division will contain 31 chromosomes.
When these gametes will fuse then zygote will be formed with 32+ 31 = 63 chromosomes. Since the mule contains 63 chromosomes, therefore they are sterile organisms.
Thus, true is the correct answer.
<span> Erosion is a natural process, though it is often increased by humans’ use of the land. Deforestation, overgrazing, construction, and road building often expose soil and sediments and lead to increased erosion. </span>
Answer :Erwin Chargaff a Biochemist
Explanation:
He formulated the base paring of double helix of DNA. He reasoned that since the percentage of four DNA bases are of this proportions in human;
Adenine=30.9% and Thymine =29.4%;
Guanine=19.9% and Cytosine =19.8%
Then, the amount of adenine will always be equal to thymine,
And the amount of Guanine equals to cytosine based on this percentages of distribution.
(Adenine and Guanine are large, molecule of Purines, while thymine and Cytosine are Pyrimidine)
He concluded (although scientist believed, he did not explicitly stated this) that this should be the base paring patterns in DNA molecule. This is the first Chargaff Rule.
His second rule is that the DNA composition, in the relative amount of the four bases Adenine, Thymine, Cytosine and Guanine varies in proportion from one organisms to another. And this is the basis of molecular diversity.
