1. Which of the following can weaken the immune system and increase susceptibility to infections?

A. Regular exercise
B. Balanced diet
C. Chronic stress
D. Adequate sleep

Correct answer: C

Rationale: Chronic stress can weaken the immune system by increasing the production of stress hormones like cortisol, which can suppress immune function over time. Prolonged stress can also lead to inflammation, making the body more vulnerable to infections. It is important to manage stress levels through relaxation techniques, exercise, and seeking support to maintain a healthy immune system.

2. Which sentence uses the present perfect continuous tense correctly?

A. I have been working on this project since morning.
B. She has finished the book already.
C. They will be leaving for vacation tomorrow.
D. He had been living in the city for ten years.

Correct answer: A

Rationale: Option A emphasizes the ongoing action (working) that started in the past and continues to the present.

3. Which hormone, produced by the adrenal glands, helps regulate the body's response to stress, including increasing blood pressure and suppressing the immune system?

A. Aldosterone
B. Epinephrine
C. Cortisol
D. Insulin

Correct answer: c

Rationale: The correct answer is C: Cortisol. Cortisol is a hormone produced by the adrenal glands that plays a crucial role in the body's response to stress. It helps regulate blood pressure by increasing it to prepare the body for stressors. Additionally, cortisol suppresses the immune system to prioritize the stress response. Aldosterone, while also produced by the adrenal glands, primarily regulates electrolyte balance and blood pressure. Epinephrine, produced by the adrenal medulla, is involved in the fight-or-flight response but does not suppress the immune system like cortisol. Insulin, produced by the pancreas, regulates blood sugar levels and is not directly involved in the stress response. Therefore, Cortisol is the hormone that specifically helps regulate the body's response to stress by increasing blood pressure and suppressing the immune system.

4. Simplify the expression: -5 + (-8)

A. -13
B. 8
C. 13
D. -5

Correct answer: A

Rationale: Combine the negative signs by adding them together. -5 + (-8) = -13

5. What is the difference between homologous chromosomes and sister chromatids?

A. Homologous chromosomes have the same genes but may have different alleles, while sister chromatids are identical copies of the same chromosome.
B. Homologous chromosomes are only found in diploid cells, while sister chromatids are found in both haploid and diploid cells.
C. Both homologous chromosomes and sister chromatids are genetically identical, but only sister chromatids separate during mitosis.
D. Both homologous chromosomes and sister chromatids can separate during mitosis, but only homologous chromosomes have different alleles.

Correct answer: A

Rationale: Rationale: - Homologous chromosomes are pairs of chromosomes that have the same genes in the same order, one from each parent. While they carry the same genes, they may have different alleles (variants of a gene). - Sister chromatids are exact copies of each other, formed during DNA replication. They are held together by a centromere and are produced during the S phase of the cell cycle. - During meiosis, homologous chromosomes pair up and exchange genetic material through crossing over, leading to genetic variation. Sister chromatids separate during mitosis to ensure each daughter cell receives an identical copy of the genetic material.