One harmful substance that can pass through the placenta is nicotine. It is an alkaloid found in the nightshade family of plants.

Nicotine can cause brain damage or low birth weight if consumed by pregnant women.

The structure in the uterus where the exchange of material between the mother and the developing fetus takes place is the placenta. The placenta supplies the fetus with maternal nutrients, and allows fetal waste to be disposed of via the maternal kidneys.

Testosterone influences the formation of sperm cells

Testosterone is a reproductive hormone.

Testosterone influences the formation of sperm cells which are essential in the process of sexual reproduction be human beings. While the testosterone hormone is not directly responsible for manufacturing sperm cells, it is still a part of the process. A man's testis are primarily responsible for two things: sperm cell production, and testosterone production. When testosterone levels drop in the body, a sequence of triggers tells the testis to produce more testosterone and more sperm.

Correct Answer – Option 4 – The level of testosterone may start to decrease

Gland C in males is responsible for production of testosterone. Hence, if the interaction of the pituitary gland with gland C is blocked, the level of testosterone may start to decrease. Hence, option 4 is correct.

Progesterone is a hormone produced in females. Hence, option 1 is incorrect.

The pituitary gland is not evolved to replace a hormone. Hence, option 2 is incorrect.

Gland A is not equipped with receptors to interact with hormone 3. Hence, option 3 is incorrect.

Correct Answer – Option 4 - D

An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination. In humans, it is called an embryo from the moment of implantation until the end of the 8th week, where after it is instead called a fetus. The Embryo grows by mitosis which represents division of the cells for growth.

Mitosis is the process in which a eukaryotic cell separates the chromosomes in its cell nucleus, into two identical sets in two daughter nuclei.[1] It is generally followed immediately by cytokinesis, which divides the nuclei, cytoplasm, organelles and cell membrane into two daughter cells containing roughly equal shares of these cellular components. Mitosis and cytokinesis together define the mitotic (M) phase of the cell cycle - the division of the mother cell into two daughter cells, genetically identical to each other and to their parent cell.

Correct Answer – Option 2 – asexual reproduction

Asexual reproduction is a method of reproduction where only one parent undergoes reproduction resulting in an offspring genetically identical to the clone. Commercially-important plants are often deliberately propagated by asexual means in order to keep particularly desirable traits such as flower color, flavor, etc. This technique of cutting the stem or branch of a parent and rooting this to grow another plant is known as grafting.

Sexual reproduction, gamete production and gene manipulation are methods of reproducing sexually with the involvement of 2 parents resulting in 1 or more offspring. Hence, options 1,3 and 4 are incorrect.

Correct Answer – Option 1

According to the diagram all genetic material comes from 1 parent. Hence, option 1 is correct.

The cell is divided into 2 equal halves. Hence, option 2 is incorrect.

There is no relation to the size of the parent to the genetic material. Hence, option 3 is incorrect.

There is no information about the relationship of the source of the genetic material and the size of the parent. Hence, option 4 is incorrect.

• Materials can diffuse out of the mother’s capillaries into the baby’s capillaries.
• Harmful substances can diffuse/pass through the walls of capillaries.
• Molecules pass through the placenta.

Option 2 - B
Part B is the ovary which produces gametes in the female reproductive system.