Regents Living Environment 5 — Questions and Answers
Question 1: A species of bird develops a longer beak over many generations to reach nectar deep inside flowers. Which mechanism best explains this change?
- Genetic engineering by scientists
- Natural selection favoring longer beaks for survival (Correct answer)
- Individual birds purposely growing longer beaks
- Random genetic drift with no selection pressure
Correct answer: Natural selection favoring longer beaks for survival
Natural selection favored birds with longer beaks that could access more food, increasing their survival and reproduction rates over generations.
Question 2: Which best describes the function of the cell membrane?
- It produces energy for the cell
- It controls which substances enter and exit the cell (Correct answer)
- It stores the cell's genetic information
- It synthesizes proteins for the cell
Correct answer: It controls which substances enter and exit the cell
The cell membrane is selectively permeable, regulating the movement of substances into and out of the cell to maintain homeostasis.
Question 3: Global warming is expected to cause the extinction of polar bear populations primarily because:
- Polar bears will be hunted more by humans
- Melting sea ice reduces habitat and hunting grounds for polar bears (Correct answer)
- Warmer temperatures cause genetic mutations in polar bears
- Polar bears cannot survive any temperature above freezing
Correct answer: Melting sea ice reduces habitat and hunting grounds for polar bears
Polar bears rely on sea ice for hunting seals; as global warming melts Arctic ice, their habitat shrinks and food becomes inaccessible.
Question 4: Which best explains why identical twins have the same DNA but may develop different traits?
- Their DNA mutates differently after birth
- Environmental factors influence gene expression differently (Correct answer)
- One twin receives more chromosomes than the other
- Meiosis creates different versions of genes in each twin
Correct answer: Environmental factors influence gene expression differently
Environmental factors such as diet, stress, and experiences can influence gene expression (epigenetics), leading to different traits despite identical DNA.
Question 5: A scientist studying a lake ecosystem notes that phosphorus levels are extremely low. This phosphorus limitation would most directly affect:
- The rate of evaporation from the lake
- The growth rate of producers in the lake (Correct answer)
- The body temperature of fish in the lake
- The speed at which water flows through the lake
Correct answer: The growth rate of producers in the lake
Phosphorus is a key nutrient for plant growth; low phosphorus levels would limit the growth of algae and aquatic plants (producers) in the ecosystem.
Question 6: Which statement best describes why vaccines are effective at preventing disease?
- Vaccines kill pathogens before they enter the body
- Vaccines stimulate the immune system to produce memory cells against specific pathogens (Correct answer)
- Vaccines replace damaged cells caused by infection
- Vaccines contain antibiotics that destroy bacteria
Correct answer: Vaccines stimulate the immune system to produce memory cells against specific pathogens
Vaccines introduce weakened or inactivated antigens, triggering the immune system to produce memory cells so future exposure causes a rapid immune response.
Question 7: Two species of birds live in the same forest but feed at different times of day and in different areas of trees. This behavior most likely reduces:
- Mutualism between the species
- Competition between the species (Correct answer)
- Predation rates on both species
- Genetic variation within each species
Correct answer: Competition between the species
By using different resources (time and space), the two species reduce direct competition with each other, a concept called niche differentiation.
Regents Living Environment 5
A species of bird develops a longer beak over many generations to reach nectar deep inside flowers.
Which mechanism best explains this change?