Since ALD is an x-linked recessive disease, women must have 2 affected x chromosomes in order to get the disease, which is unlikely because the disease is rare. Since men only have one x chromosome, they will have the disease if they inherit an affected x chromosome.
Answer:
The correct answer is option - d. Production of primary spermatocytes.
Explanation:
The accessory cells or supporting cells present within the seminiferous tubules of reproductive system termed as the Sertoli cells. They play various roles in the body and reproductive system.
Sertoli cells make blood-testis barrier in adjacent Sertoli cells in the seminiferous tubules. These cells secrete different types of enzymes and hormones such as inhibin which are also secreted by ovary and placenta in females. Sertoli cells produce seminiferous tubular fluid to provide nutrition to the sperm. Apoptotic germ cells are timely eliminated by these cells.
Thus, the correct answer is option D. Production of primary spermatocytes.
In the chemical process of photosynthesis water is a chemical change
I hope that's help !
The answer is Permian-Triassic extinction.
The Permian-Triassic extinction was 252 million years ago. It is known as The Great Dying because about 95% of all species died out due to environmental changes (volcanic eruptions, dry climate, melting of ice sheets, etc). This is also the only event in which many insect species wiped out.
Answer:Both on the leading strand and on each okazaki fragments of the lagging strand.
Explanation:
A primer is a short single-stranded RNA nucleotide that initiate DNA synthesis at the replication fork. Because DNA polymerase can not initiate replication on it own short strand of RNA primer synthesized by an enzyme RNA primase is needed to initiate DNA polynucleotide synthesis.
RNA primer is present on both leading and lagging strand.
RNA primer of about 10 nucleotides long are present on the leading strand and on each okazaki fragments on the lagging strand to initiate replication. The RNA primer is removed and replaced by DNA nucleotides by DNA polymerase.
