Nokea
What phenomenon is responsible for the creation of rainbows?
- A. Reflection only
- B. Diffraction
- C. Refraction and reflection
- D. Polarization
Correct Answer: C
Rationale: Rainbows are created by both refraction and reflection of sunlight within water droplets in the atmosphere. When sunlight enters a water droplet, it is refracted, then internally reflected, and finally refracted again as it exits the droplet. This process causes the separation of light into its component colors and the formation of a rainbow. Choice A is incorrect because rainbows are not solely formed by reflection. Choice B, diffraction, is not the primary phenomenon responsible for rainbows. Choice D, polarization, is not directly involved in the creation of rainbows. Therefore, the correct answer is C.
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What does the number of protons in the nucleus of an atom determine?
- A. Mass number
- B. Atomic number
- C. Isotope
- D. Valence electron count
Correct Answer: B
Rationale: The number of protons in the nucleus of an atom is referred to as the atomic number. This atomic number is crucial as it uniquely identifies an element and determines its position on the periodic table. The mass number, on the other hand, represents the sum of protons and neutrons in an atom's nucleus. Isotopes are variants of elements with the same number of protons but differing numbers of neutrons. Valence electron count pertains to the number of electrons in the outermost energy level of an atom, which influences its chemical behavior.
In a food chain, which trophic level captures energy from the sun?
- A. Decomposers
- B. Carnivores
- C. Producers
- D. Omnivores
Correct Answer: C
Rationale: Producers, such as plants, algae, and some bacteria, are the organisms in a food chain that capture energy from the sun through the process of photosynthesis. They convert sunlight into chemical energy, which is then passed on to other organisms in the food chain. Producers are at the base of the food chain and form the foundation for all other trophic levels to obtain energy. Decomposers (option A) break down organic matter, carnivores (option B) consume other animals, and omnivores (option D) consume both plants and animals, but they do not directly capture energy from the sun.
Which hormone, produced by the adrenal glands, helps regulate the body's response to stress, including increasing blood pressure and suppressing the immune system?
- A. Aldosterone
- B. Epinephrine
- C. Cortisol
- D. Insulin
Correct Answer: C
Rationale: Cortisol is the correct answer. It is the hormone produced by the adrenal glands that helps regulate the body's response to stress. Cortisol plays a crucial role in increasing blood pressure and suppressing the immune system during stressful situations. Aldosterone, another hormone from the adrenal glands, primarily regulates salt and water balance in the body, not the stress response. Epinephrine, also known as adrenaline, is produced by the adrenal glands in response to stress, but its effects are more immediate and short-lived compared to cortisol. Insulin, produced by the pancreas, regulates blood sugar levels and is not directly involved in the body's response to stress.
Describe the mechanism by which genes are transmitted from parents to offspring.
- A. Blending of parental genes, resulting in an average of their traits.
- B. Random assortment of alleles during meiosis, leading to unique combinations in each offspring.
- C. Inheritance of solely dominant alleles, masking the influence of recessive ones.
- D. Direct transfer of both parental genomes, creating identical copies of the parents.
Correct Answer: B
Rationale: A) Blending of parental genes, resulting in an average of their traits, is not an accurate description of how genes are transmitted. In reality, genes are not blended but rather passed down in discrete units.
B) Random assortment of alleles during meiosis is the correct mechanism by which genes are transmitted from parents to offspring. During meiosis, homologous chromosomes separate, and alleles are randomly distributed to the gametes, leading to unique combinations of genes in each offspring.
C) Inheritance of solely dominant alleles, masking the influence of recessive ones, is not an accurate representation of gene transmission. Offspring inherit alleles from both parents, and the expression of dominant or recessive traits depends on the specific combination of alleles.
D) Direct transfer of both parental genomes, creating identical copies of the parents, is not how genes are transmitted. Offspring inherit a unique combination
Muscle soreness after exercise is often caused by microscopic tears in muscle fibers. This is called
- A. Atrophy
- B. Hypertrophy
- C. DOMS (Delayed Onset Muscle Soreness)
- D. Spasm
Correct Answer: C
Rationale: Muscle soreness after exercise is often caused by microscopic tears in muscle fibers, leading to Delayed Onset Muscle Soreness (DOMS). Atrophy refers to the wasting away of muscle tissue, hypertrophy is the increase in muscle size, and spasm is an involuntary contraction of a muscle. DOMS typically occurs 24 to 72 hours after intense exercise and is characterized by muscle stiffness, tenderness, and reduced range of motion. It is a normal response to unfamiliar or strenuous physical activity and indicates that the muscles are adapting to the workload. Therefore, the correct answer is C (DOMS) as it specifically describes the phenomenon of muscle soreness resulting from microscopic tears in muscle fibers, distinguishing it from the other choices which refer to different physiological processes or conditions.