Regents Living Environment 3

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:

Accepted Answer

Natural selection

Answer

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?

Accepted Answer

They recycle nutrients by breaking down dead organic matter

Answer

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?

Accepted Answer

Both pH and amount of enzyme

Answer

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?

Accepted Answer

Snake

Answer

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?

Accepted Answer

Meiosis

Answer

Meiosis is the type of cell division that produces haploid gametes (sperm and egg cells) with half the chromosome number of body cells.

Regents Practice Test

Regents Practice Test

Regents Living Environment 3