Regents Living Environment 3 — Questions and Answers
Question 1: An antibiotic kills 99% of a bacterial population. The surviving 1% reproduces rapidly. Over time, the population becomes antibiotic-resistant. This is an example of:
- Lamarckian inheritance
- Natural selection (Correct answer)
- Genetic engineering
- Artificial selection
Correct answer: Natural selection
Natural selection favors individuals with traits (antibiotic resistance) that improve survival, allowing those traits to increase in the population.
Question 2: Which statement best describes the role of decomposers in an ecosystem?
- They convert sunlight into chemical energy
- They recycle nutrients by breaking down dead organic matter (Correct answer)
- They produce oxygen through photosynthesis
- They consume living organisms for energy
Correct answer: They recycle nutrients by breaking down dead organic matter
Decomposers break down dead organisms and waste, returning nutrients to the soil and completing nutrient cycles.
Question 3: A student wants to test whether temperature affects enzyme activity. Which variable should be kept constant in a controlled experiment?
- Temperature
- pH of the solution
- Amount of enzyme added
- Both pH and amount of enzyme (Correct answer)
Correct answer: Both pH and amount of enzyme
In a controlled experiment, all variables except the independent variable (temperature) must remain constant, including pH and enzyme concentration.
Question 4: The diagram of a food web shows grass → grasshopper → frog → snake → hawk. If the frog population suddenly decreases, which population would most likely decrease next?
- Grass
- Grasshopper
- Snake (Correct answer)
- Hawk
Correct answer: Snake
Snakes depend on frogs as a food source, so a decrease in frogs would reduce the food supply for snakes, causing their population to decline.
Question 5: Which process directly produces gametes in sexually reproducing organisms?
- Mitosis
- Binary fission
- Meiosis (Correct answer)
- Budding
Correct answer: Meiosis
Meiosis is the type of cell division that produces haploid gametes (sperm and egg cells) with half the chromosome number of body cells.
Question 6: A scientist discovers that two distantly related species have similar bone structures in their front limbs. These structures are called:
- Vestigial structures
- Analogous structures
- Homologous structures (Correct answer)
- Derived structures
Correct answer: Homologous structures
Homologous structures are anatomically similar structures in different species that share a common ancestor, indicating evolutionary relationship.
Question 7: Insulin is a protein hormone that regulates blood sugar levels. Which organelle is primarily responsible for synthesizing insulin?
- Golgi apparatus
- Mitochondrion
- Ribosome (Correct answer)
- Lysosome
Correct answer: Ribosome
Ribosomes are the site of protein synthesis where amino acids are assembled into proteins like insulin based on mRNA instructions.
Regents Living Environment 3
An antibiotic kills 99% of a bacterial population.
The surviving 1% reproduces rapidly.
Over time, the population becomes antibiotic-resistant.
This is an example of: