Question

the graph shows changes over time in a population of bacteria added to a test tube of growth medium. what activity characterizes the growth cycle during phase ii?
a bacteria are weakening due to the accumulation of waste products.
b bacteria are increasing in metabolic activity though not dividing.
c bacteria are dying off rapidly from lack of nutrients and space.
d bacteria are dividing regularly by binary fission.
if b is your answer, click the next button. otherwise, select another answer.

Explanation:

Step1: Analyze each phase

• Phase I: Lag phase. Bacteria are adjusting to the environment, increasing metabolic activity but not dividing (eliminates B).
• Phase II: Logarithmic (exponential) phase. Bacteria divide regularly by binary fission, population increases rapidly.
• Phase III: Stationary phase. Growth rate slows as nutrients are depleted and waste accumulates.
• Phase IV: Death phase. Bacteria die off rapidly due to lack of nutrients and space (eliminates A and C).

Answer:

D. Bacteria are dividing regularly by binary fission.