1. Antidiuretic hormone (ADH) helps the kidneys regulate:

A. Acid-base balance
B. Blood pressure
C. Urine output by controlling water reabsorption
D. All of the above

Correct answer: C

Rationale: The correct answer is C: 'Urine output by controlling water reabsorption.' Antidiuretic hormone (ADH) is released by the pituitary gland and acts on the kidneys to regulate water reabsorption. When ADH levels are high, the kidneys reabsorb more water, leading to concentrated urine and decreased urine output. This helps maintain the body's water balance and prevent dehydration. While ADH indirectly influences blood pressure by regulating blood volume, its primary function is to control water balance, not acid-base balance. Therefore, the correct answer is C.

2. The primary function of the placenta during pregnancy is to:

A. Produce insulin
B. Facilitate gas exchange between mother and fetus
C. Excrete waste products from the fetus
D. All of the above

Correct answer: D

Rationale: The correct answer is D, 'All of the above.' The placenta serves multiple crucial functions during pregnancy. It facilitates gas exchange between the mother and fetus, ensuring the transfer of oxygen and nutrients while removing carbon dioxide and waste products. Additionally, the placenta produces hormones like insulin that help regulate the mother's metabolism and support the development of the fetus. Therefore, the placenta plays a vital role in maintaining a healthy environment for the growing fetus by providing essential nutrients, removing waste, and regulating hormonal balance.

3. What type of bond forms between elements when they share electrons?

A. Covalent bond
B. Ionic bond
C. Metallic bond
D. Hydrogen bond

Correct answer: A

Rationale: In a covalent bond, atoms share electrons, creating a strong attraction that holds them together

4. Which of the following is a unit of measurement for energy?

A. Watt (W)
B. Joule (J)
C. Newton (N)
D. Kilogram (kg)

Correct answer: b

Rationale: Energy is measured in Joules (J) in the SI unit system.

5. What is the process by which a fertilized egg implants itself in the lining of the uterus?

A. Fertilization
B. Implantation
C. Gestation
D. Parturition

Correct answer: B

Rationale: The correct answer is B: Implantation. Implantation is the process by which a fertilized egg, or zygote, attaches itself to the uterine wall to establish a pregnancy. Fertilization is the fusion of sperm and egg to form a zygote, which occurs in the fallopian tube. Gestation refers to the period of development of the fetus inside the uterus. Parturition is the process of giving birth. Therefore, implantation specifically refers to the attachment of the fertilized egg to the uterine lining, making it the most appropriate answer in this context.

6. Which of the following properties is NOT characteristic of a covalent bond?

A. Sharing of electrons between atoms
B. High melting and boiling points
C. Low electrical conductivity in solid state
D. Directional bonding

Correct answer: B

Rationale: Covalent bonds are formed by the sharing of electrons between atoms. This sharing results in the formation of molecules with directional bonding, where the atoms are held together in a specific orientation. Covalent compounds generally have low melting and boiling points compared to ionic compounds, as the intermolecular forces in covalent compounds are weaker. Additionally, covalent compounds do not conduct electricity in the solid state because the electrons are localized between the atoms and not free to move and carry charge.