Nokea
How many pairs of homologous chromosomes do humans have?
- A. 13
- B. 23
- C. 26
- D. 46
Correct Answer: D
Rationale: The correct answer is D: 46. Humans have 23 pairs of chromosomes, which include 22 pairs of autosomes and 1 pair of sex chromosomes. Homologous chromosomes are pairs of chromosomes that contain the same genes, one from each parent. Therefore, humans have a total of 46 chromosomes, with 23 pairs of homologous chromosomes. Choices A, B, and C are incorrect as they do not represent the total number of chromosomes in humans or the number of pairs of homologous chromosomes.
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If both parents have polydactylism, what percentage of their offspring is predicted to manifest the anomaly?
- A. 25%
- B. 50%
- C. 75%
- D. 100%
Correct Answer: B
Rationale: When both parents have polydactylism, they each possess at least one dominant allele for polydactylism. Through a Punnett square analysis, it can be determined that 50% of their offspring will inherit the dominant allele from both parents. This results in a 100% chance of manifesting the anomaly (2 out of 4 possibilities). Therefore, 50% of the offspring are predicted to manifest the anomaly. Choices A, C, and D are incorrect as they do not align with the principles of Mendelian genetics and Punnett square analysis.
Which is a byproduct of fermentation in muscle cells?
- A. Ethanol
- B. Pyruvic acid
- C. Lactic acid
- D. Oxygen
Correct Answer: C
Rationale: Lactic acid is a byproduct of fermentation in muscle cells. During intense exercise or when oxygen is limited, muscle cells use anaerobic respiration to generate energy. This process breaks down glucose into lactic acid, which can cause muscle fatigue and soreness. Choice A, Ethanol, is not produced in muscle cells during fermentation. Choice B, Pyruvic acid, is an intermediate product in glucose metabolism but is not a byproduct of fermentation in muscle cells. Choice D, Oxygen, is not a byproduct of fermentation but a reactant in aerobic respiration.
Which light color would be most effective for growing green plants indoors?
- A. Blue
- B. Yellow
- C. Green
- D. Orange
Correct Answer: A
Rationale: Blue light is the most effective color for growing green plants indoors. Blue light has a higher energy level compared to other colors, which is crucial for promoting vegetative growth, strong stems, and lush foliage in plants. Additionally, blue light helps regulate plant growth hormones, making it essential for the overall health and development of green plants. Yellow, green, and orange light do not provide the necessary energy levels or spectrum needed for optimal plant growth, making them less effective choices for growing green plants indoors.
Ocean waves may tear sponges into pieces, each of which may grow into a new sponge. What is this form of reproduction called?
- A. Budding
- B. Vegetative propagation
- C. Binary fission
- D. Fragmentation
Correct Answer: D
Rationale: Fragmentation is the form of asexual reproduction where an organism breaks into fragments, and each fragment can grow into a new individual. In the case of sponges being torn into pieces by ocean waves, each piece has the potential to develop into a new sponge, making fragmentation the correct answer in this scenario. Budding is a form of asexual reproduction where a new organism develops as an outgrowth from the parent organism. Vegetative propagation involves the growth of new individuals from plant parts like stems or roots. Binary fission is a method of reproduction seen in some single-celled organisms where one cell divides into two identical cells.
Dogs are part of a larger animal group, the Carnivora. What classification is this?
- A. Kingdom
- B. Class
- C. Order
- D. Genus
Correct Answer: C
Rationale: The classification 'Carnivora' refers to an order in the taxonomic hierarchy. In the Linnaean classification system, the order comes below the class but above the family level. Therefore, Carnivora is a higher classification that includes dog species as well as other carnivorous mammals like cats, bears, and weasels. Option A (Kingdom) is too broad and refers to the highest taxonomic rank. Option B (Class) is a lower taxonomic rank than order. Option D (Genus) is a much more specific rank that comes below the family level in the Linnaean hierarchy.