Nokea
Which element is used in semiconductors like computer chips and solar panels?
- A. Germanium
- B. Silicon
- C. Gallium
- D. Arsenic
Correct Answer: B
Rationale: Silicon is the correct answer. Silicon is widely used in semiconductors for electronic applications because of its unique properties that allow it to be manipulated to conduct or not conduct electricity effectively. Germanium is also used in semiconductors but to a lesser extent compared to silicon. Gallium and arsenic are not as commonly used in semiconductors like computer chips and solar panels, making them incorrect choices for this question.
You may also like to solve these questions
Which of the following joints allows for side-to-side bending movements?
- A. Hinge joint
- B. Ball-and-socket joint
- C. Gliding joint
- D. Saddle joint
Correct Answer: C
Rationale: The correct answer is C, Gliding joint. Gliding joints allow for side-to-side bending movements. These joints are found between the small bones of the wrist and ankle, allowing for flexibility and movement in multiple directions. Hinge joints (A) enable movement in one plane, akin to a door hinge. Ball-and-socket joints (B) allow for a wide range of motion across multiple directions. Saddle joints (D) facilitate movement in two planes.
The immune response can be categorized into two main branches:
- A. Humoral and cellular
- B. Innate and adaptive
- C. Primary and secondary
- D. Active and passive
Correct Answer: A
Rationale: - The immune response can be broadly categorized into two main branches: the humoral immune response and the cellular immune response.
- The humoral immune response involves the production of antibodies by B cells and is primarily responsible for defending against extracellular pathogens such as bacteria and viruses in the bloodstream and tissues.
- The cellular immune response involves the activation of T cells, which can directly kill infected cells or help coordinate the immune response. This branch is crucial for combating intracellular pathogens like viruses and some bacteria.
- Options B, C, and D do not accurately represent the main branches of the immune response and are therefore incorrect.
The adrenal cortex produces a group of steroid hormones called corticosteroids. What is a MAJOR function of corticosteroids?
- A. Regulate insulin sensitivity and blood sugar levels
- B. Control blood pressure and electrolyte balance
- C. Stimulate the immune system and inflammatory response
- D. Promote growth and development during puberty
Correct Answer: B
Rationale: Corticosteroids, produced by the adrenal cortex, primarily function to control blood pressure and electrolyte balance. One of the key corticosteroids, aldosterone, plays a crucial role in regulating sodium and potassium levels in the body. This regulation is essential for maintaining blood pressure and electrolyte balance. Choices A, C, and D are incorrect because corticosteroids do not primarily regulate insulin sensitivity and blood sugar levels, stimulate the immune system and inflammatory response, or promote growth and development during puberty. While corticosteroids can have effects on insulin sensitivity, immune response, and growth, their major role is in maintaining blood pressure and electrolyte balance.
Which of the following is an example of stabilizing selection?
- A. Selection that favors extreme traits in a population
- B. Selection that removes individuals with extreme traits
- C. Selection that maintains the current average trait in a population
- D. Selection that favors one specific trait over all others
Correct Answer: C
Rationale: - Stabilizing selection is a type of natural selection that favors the intermediate variants in a population, while selecting against the extreme traits. This results in the maintenance of the current average trait in the population.
- Option A is incorrect because stabilizing selection does not favor extreme traits; instead, it favors the average trait.
- Option B is incorrect because stabilizing selection does not remove individuals with extreme traits; it acts against extreme traits by favoring the intermediate variants.
- Option D is incorrect because stabilizing selection does not favor one specific trait over all others; it favors the average trait by selecting against extreme traits.
How does urine flow through the urethra?
- A. Continuously
- B. Only when the bladder is completely full
- C. Under voluntary control of sphincter muscles
- D. A combination of B and C
Correct Answer: C
Rationale: Urine flows through the urethra under voluntary control of sphincter muscles. These muscles can be consciously contracted or relaxed to control the flow of urine from the bladder to the outside of the body. Choice A is incorrect as urine flow is not continuous but rather regulated. Choice B is incorrect because urine flow is not restricted to only when the bladder is completely full. Choice D is incorrect as it inaccurately combines the two incorrect statements of choices B and C.