Which of the following is true regarding exponential growth?

No population can grow exponentially for long.

The correct answer is option (1): No population can grow exponentially for long.

Exponential growth is a theoretical concept that assumes unlimited resources and ideal conditions. In reality, no population can sustain exponential growth indefinitely. Eventually, limiting factors such as resource availability, predation, competition, and disease come into play, causing the growth rate to slow down and reach a more sustainable level.

Option (2) is incorrect because exponential growth does not slow down as it nears its log phase. Instead, it is characteristic of logistic growth, where the growth rate decreases as the population approaches its carrying capacity.

Option (3) is also incorrect because bacterial colonies, like any other population, cannot maintain exponential growth indefinitely. They eventually reach a point where the availability of resources becomes limited, leading to a decrease in the growth rate.

Option (4) is not accurate because exponential growth is typically observed in populations with short generation times, such as microorganisms or small animals with rapid reproduction rates. Algal populations, which include various types of photosynthetic microorganisms, have been observed to exhibit exponential growth under favorable conditions.

In summary, exponential growth is not sustainable in the long term, and it is limited by various factors that cause the growth rate to slow down and approach a steady state.