1. Melanin, the pigment responsible for skin color, is produced by

A. Keratinocytes (These cells produce keratin)
B. Melanocytes
C. Sebocytes (These cells produce sebum)
D. Langerhans cells (These cells are part of the immune system)

Correct answer: B

Rationale: The correct answer is B: Melanocytes. Melanin, the pigment responsible for skin color, is produced by melanocytes, which are specialized cells located in the skin's epidermis. Melanocytes transfer melanin to keratinocytes, the predominant cell type in the epidermis, where it provides protection against UV radiation. Sebocytes produce sebum, an oily substance that helps moisturize the skin and hair. Langerhans cells are a type of immune cell that play a role in the skin's immune response. Therefore, the correct answer is B as melanocytes are specifically responsible for producing melanin.

2. What is the periodic table?

A. A table of elements that are arranged in order of increasing atomic number.
B. A table of elements that are arranged in order of increasing atomic mass.
C. A table of elements that are arranged in order of their reactivity.
D. A table of elements that are arranged in order of their color.

Correct answer: B

Rationale: The periodic table is a tabular arrangement of the chemical elements, organized on the basis of their atomic number, electron configurations, and recurring chemical properties. Elements are arranged in rows (periods) and columns (groups) with similar properties. The elements are listed in order of increasing atomic number, which is the number of protons in the nucleus of an atom. This arrangement reveals a periodic repetition of chemical properties, which is the basis of the periodic law.

3. Which functional group is commonly found in ketones?

A. Hydroxyl
B. Carbonyl
C. Ester
D. Amine

Correct answer: B

Rationale: Ketones have the functional group -CO-, which is a carbonyl group. The other choices are associated with different functional groups

4. Identify the interjection in the following sentence: Ouch! I stubbed my toe on the table leg.

A. table
B. leg
C. ouch
D. stubbed

Correct answer: C

Rationale: Interjections express emotions or sudden feelings. "Ouch" conveys a feeling of pain.

5. Delta waves, associated with deep sleep, exhibit what frequency range?

A. 0.5-4 Hz
B. 4-8 Hz
C. 8-13 Hz
D. 13-30 Hz

Correct answer: A

Rationale: Delta waves are slow brainwaves that are typically associated with deep sleep stages, such as stages 3 and 4 of non-REM sleep. These waves have a frequency range of 0.5-4 Hz, making option A the correct answer. During deep sleep, the brain slows down significantly, and delta waves are prominent on an electroencephalogram (EEG). The frequency range of 4-8 Hz corresponds to theta waves, which are more commonly observed during light sleep or drowsiness. Alpha waves fall within the 8-13 Hz range and are typically seen when an individual is awake but relaxed. Beta waves, ranging from 13-30 Hz, are associated with alertness and active thinking. Therefore, option A is the correct choice for delta waves, reflecting their slow frequency characteristic during deep sleep.