Random changes in allele frequency in a population are usually called genetic drift. The reason why this is the answer is because it is a very specific word which is used to describe exactly that - random changes in allele frequency.
All the other cases; answers, here aren't correct and don't apply.
Answer: option A - bottleneck effect
Explanation:
Whenever sudden change caused by human or natural disasters occurs in the environment leading to the reduction of organisms or biodiversity present to a lower size, such condition is referred to as BOTTLENECK EFFECT.
Answer:
In plants and algae, which developed much later, photosynthesis occurs in a specialized intracellular organelle—the chloroplast. Chloroplasts perform photosynthesis during the daylight hours. The immediate products of photosynthesis, NADPH and ATP, are used by the photosynthetic cells to produce many organic molecules.
Algae because it is a small organism that the larva state of animals live in and feed on it