1. The hormone responsible for milk production in the breasts after childbirth is:

A. Estrogen
B. Prolactin
C. Oxytocin
D. Relaxin

Correct answer: B

Rationale: The correct answer is B: Prolactin. Prolactin is the hormone responsible for milk production in the breasts after childbirth. It is produced by the pituitary gland and stimulates the alveoli in the breasts to produce milk. Estrogen plays a role in breast development during pregnancy but is not responsible for milk production. Oxytocin is responsible for the ejection of milk from the breasts during breastfeeding. Relaxin is a hormone that helps prepare the body for childbirth by relaxing the ligaments in the pelvis. Therefore, the hormone directly responsible for milk production after childbirth is prolactin.

2. What is the difference between polygenic inheritance and pleiotropy?

A. Polygenic inheritance involves multiple genes influencing one trait, while pleiotropy involves one gene affecting multiple traits.
B. Polygenic inheritance is found in simple Mendelian traits, while pleiotropy is found in complex traits.
C. Polygenic inheritance is always quantitative, while pleiotropy can be qualitative or quantitative.
D. Both involve multiple genes and multiple traits, but the specific mechanisms differ

Correct answer: A

Rationale: Rationale: - Polygenic inheritance refers to the situation where a trait is influenced by multiple genes, each contributing a small effect to the phenotype. These traits often show continuous variation and are not easily categorized into discrete categories. - Pleiotropy, on the other hand, occurs when a single gene influences multiple, seemingly unrelated traits. This means that a mutation in one gene can lead to multiple phenotypic effects across different traits or characteristics. - Therefore, the key difference between polygenic inheritance and pleiotropy lies in the number of genes involved in influencing a trait (multiple genes in polygenic inheritance vs. one gene in pleiotropy) and the direction of influence (one trait affected by multiple genes in polygenic inheritance vs. multiple traits affected by one gene in pleiotropy).

3. Which of the following substances is an example of an acidic gas?

A. Nitrogen (Nâ‚‚)
B. Carbon dioxide (COâ‚‚)
C. Sulfur dioxide (SOâ‚‚)
D. Oxygen (Oâ‚‚)

Correct answer: C

Rationale: Sulfur dioxide is an acidic gas. The other choices are either neutral or basic gases.

4. What property of a substance refers to its ability to be drawn into thin wires?

A. Conductivity
B. Ductility
C. Viscosity
D. Malleability

Correct answer: b

Rationale: Ductility refers to a substance's ability to be drawn into thin wires without breaking.

5. The number of protons in an atom determines its:

A. Mass number
B. Atomic number
C. Atomic number
D. Valence electron count

Correct answer: B

Rationale: The atomic number (Z) equals the number of protons and defines an element's core identity.

6. Distinguish between the digestive and respiratory systems.

A. Mouth
B. Stomach
C. Small intestine
D. Lungs

Correct answer: D

Rationale: Rationale: - The mouth, stomach, and small intestine are all parts of the digestive system, responsible for breaking down food into nutrients that can be absorbed by the body. - The lungs are part of the respiratory system, responsible for the exchange of oxygen and carbon dioxide between the body and the environment through breathing. - While the digestive system processes food for energy and nutrients, the respiratory system is focused on the exchange of gases necessary for cellular respiration.