The antibodies to the HIV virus may take up to three months to appear in the blood of the infected person.
Therefore, the second blood test is necessary three months after a person thinks that he/she has been exposed to HIV to check the presence of these antibodies and confirm whether the person is infected or not.
Answer:
Shows the flow of food and energy
Answer: The statement is false
Explanation:
A community refers to a group of plants and animals that occupy a given area and can adapt to the conditions of their environment. Hence, community include biotic factors (living organisms) and abiotic factors (non-living factors like soil, weather etc).
Thus, the statement is false
Answer:
According to the hormone diagram of the menstrual cycle, the woman is not pregnant due to the behavior of progesterone and estrogens, whose levels do not increase, in addition to the absence of human chorionic gonadotropin.
Explanation:
The graph shows the behavior of hormones during a woman's menstrual cycle in the absence of pregnancy.
During a woman's normal cycle, estrogen, luteinizing hormone (LH) and follicle stimulating hormone (FSH) tend to increase prior to ovulation, reach their peak values at ovulation, and then decline, as shown in the graph. Progesterone, on the other hand, increases after ovulation and decreases if the woman does not become pregnant.
In the case of a pregnant woman:
- <u>Estrogens</u> continue to increase after ovulation, produced by the ovaries and placenta.
- <u>Progesterone</u> also increases its levels, as it is a hormone produced by the ovaries and placenta.
- <u>Hormone human chorionic gonadotropin</u> (HCG) appears and increases during pregnancy, due to the secretory activity of the placenta.
<em><u>The diagram represents the normal cycle of a woman who is not pregnant</u></em>.
