1. Dandruff is caused by

A. Excessive sebum production (This can contribute to oily dandruff)
B. Bacterial infection (This can cause scalp folliculitis, not dandruff)
C. Overgrowth of a specific type of fungus on the scalp
D. Lack of proper skin hydration

Correct answer: C

Rationale: Dandruff is primarily caused by an overgrowth of a specific type of fungus called Malassezia on the scalp. This fungus feeds on the natural oils produced by the hair follicles, leading to an inflammatory response in some individuals, resulting in flaking and itching. Excessive sebum production can contribute to oily dandruff by providing more food for the fungus. Bacterial infections, such as scalp folliculitis, can cause symptoms similar to dandruff but are not the primary cause. Lack of proper skin hydration can contribute to dry scalp conditions but is not the main cause of dandruff.

2. What is the difference between a homozygous recessive genotype and a homozygous dominant genotype?

A. Both have the same phenotype, but different genotypes.
B. Both have the same genotype, but different phenotypes.
C. Homozygous recessive has two dominant alleles, while homozygous dominant has two recessive alleles.
D. Homozygous recessive has two identical recessive alleles, while homozygous dominant has two identical dominant alleles.

Correct answer: D

Rationale: Rationale: - Homozygous recessive genotype refers to an individual having two identical recessive alleles for a particular gene (e.g., rr for a trait where r represents the recessive allele). - Homozygous dominant genotype refers to an individual having two identical dominant alleles for a particular gene (e.g., RR for a trait where R represents the dominant allele). - The difference between the two genotypes lies in the specific alleles present in each case, with homozygous recessive having two recessive alleles and homozygous dominant having two dominant alleles. - This genetic difference results in different phenotypes being expressed, as the dominant allele typically masks the expression of the recessive allele in heterozygous individuals.

3. Deficiency of which hormone can lead to stunted growth and developmental delays in children?

A. Estrogen
B. Testosterone
C. Growth hormone
D. Insulin

Correct answer: C

Rationale: The correct answer is C: Growth hormone. Growth hormone plays a crucial role in stimulating growth, cell reproduction, and regeneration in humans. Deficiency of growth hormone can lead to stunted growth and developmental delays in children. Estrogen and testosterone are sex hormones responsible for sexual development and characteristics, but they do not directly impact growth. Insulin is a hormone that regulates blood sugar levels and is not associated with stunted growth or developmental delays.

4. What is the pH value of a neutral solution?

A. 0
B. 7
C. 14
D. -7

Correct answer:

Rationale: A neutral solution has a pH of 7. The pH scale ranges from 0 to 14, with 7 being neutral.

5. What is the meaning of the idiom "to cross that bridge when we come to it"?

A. To deal with a problem immediately
B. To plan for the future in detail
C. To worry about potential problems prematurely
D. To avoid difficult situations

Correct answer: C

Rationale: The idiom suggests dealing with challenges as they arise, not before.

6. Which structure in the respiratory system is responsible for preventing food and liquids from entering the trachea during swallowing?

A. Bronchi
B. Larynx
C. Alveoli
D. Pharynx

Correct answer: B

Rationale: The correct answer is B: Larynx. The larynx, also known as the voice box, is a crucial structure in the respiratory system responsible for preventing food and liquids from entering the trachea during swallowing. It contains the epiglottis, a flap of tissue that covers the trachea during swallowing to ensure that food and liquids are directed to the esophagus instead of entering the airway. The bronchi are the two main branches that carry air into the lungs, while alveoli are tiny air sacs where gas exchange occurs. The pharynx is a shared pathway for both air and food, located behind the oral and nasal cavities. Therefore, the larynx plays a vital role in protecting the respiratory system during swallowing.