1. Which hormone is responsible for the characteristic changes experienced during puberty, such as breast development and menstruation in females?

A. Follicle-stimulating hormone (FSH)
B. Luteinizing hormone (LH)
C. Estrogen
D. Progesterone

Correct answer: C

Rationale: The correct answer is C: Estrogen. Estrogen plays a crucial role in regulating the development of secondary sexual characteristics during puberty in females. It is responsible for breast development, widening of hips, and the onset of menstruation. Estrogen is mainly produced by the ovaries and is essential for the maturation of the reproductive system. Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) are pituitary hormones that regulate the menstrual cycle and ovulation but do not directly cause the characteristic changes seen during puberty. Progesterone is another hormone involved in the menstrual cycle and pregnancy but is not primarily responsible for the physical changes during puberty.

2. Which energy conversion occurs in a solar cell?

A. Electrical energy to light energy
B. Chemical energy to electrical energy
C. Solar energy to thermal energy
D. Solar energy to electrical energy

Correct answer: d

Rationale: Solar cells convert solar energy (sunlight) directly into electrical energy.

3. Which of the following is a characteristic of unsaturated fatty acids?

A. They are solid at room temperature.
B. They contain only single bonds.
C. They have a higher melting point.
D. They contain double or triple bonds.

Correct answer: D

Rationale: Unsaturated fatty acids contain double or triple bonds in their hydrocarbon chains. The other choices do not accurately describe unsaturated fatty acids.

4. The gradual change in a species over time is called:

A. Adaptation
B. Evolution
C. Speciation
D. Natural selection

Correct answer: B

Rationale: Rationale: - Adaptation refers to the process by which a species becomes better suited to its environment over time. While adaptation is a component of evolution, it specifically refers to the changes that help a species survive and reproduce in its environment. - Speciation is the process by which new species arise from a single ancestral species. It involves the evolution of reproductive isolation between populations. - Natural selection is a mechanism of evolution where individuals with advantageous traits are more likely to survive and reproduce, leading to the increase in frequency of those traits in a population. - Evolution is the gradual change in a species over time, encompassing all the processes such as adaptation, speciation, and natural selection that drive these changes.

5. Which of Mendel's Laws states that alleles for a gene segregate during gamete formation?

A. Law of Independent Assortment
B. Law of Segregation
C. Law of Dominance
D. Law of Probability

Correct answer: B

Rationale: Rationale: The Law of Segregation, proposed by Gregor Mendel, states that alleles for a gene segregate during gamete formation. This means that each parent passes on only one allele for each gene to their offspring. This law explains how genetic diversity is maintained and how different combinations of alleles are generated in offspring. The Law of Independent Assortment (option A) states that alleles of different genes assort independently of each other during gamete formation. The Law of Dominance (option C) states that one allele can be dominant over another allele, affecting the phenotype. The Law of Probability (option D) is a general concept that describes the likelihood of a particular event occurring.

6. Which hormone, produced by the pineal gland, plays a role in regulating sleep-wake cycles and is often associated with the body's internal circadian rhythm?

A. Melatonin
B. Serotonin
C. Dopamine
D. Endorphin

Correct answer: a

Rationale: The correct answer is A: Melatonin. Melatonin is a hormone produced by the pineal gland that plays a crucial role in regulating sleep-wake cycles and is closely tied to the body's circadian rhythm. It is often referred to as the 'sleep hormone' because it helps signal to the body when it is time to sleep and wake up. Serotonin (option B) is a neurotransmitter that plays a role in mood regulation and happiness. Dopamine (option C) is involved in reward-motivated behavior and movement. Endorphins (option D) are neuropeptides that act as natural painkillers and contribute to feelings of pleasure. Therefore, Melatonin is the hormone associated with the body's internal circadian rhythm and sleep-wake cycles.