Explanation
Correct answer: C.
Choice C is the best answer. “Next” logically signals that the egg laying in this sentence is the next step in the sequence of events described in the other sentences.
Why the other choices are wrong
Choice A
Choice A is incorrect because “by contrast” illogically signals that the egg laying in this sentence contrasts with the nest digging in the previous sentence. Instead, the egg laying follows the nest digging as the next step in the sequence of events.
Choice B
Choice B is incorrect because “similarly” illogically signals that the egg laying in this sentence is similar to the nest digging in the previous sentence. Though the two actions are related, they are not similar. Instead, the egg laying follows the nest digging as the next step in the sequence of events.
Choice D
Choice D is incorrect because “for example” illogically signals that the egg laying in this sentence is an example of the nest digging in the previous sentence. Instead, the egg laying follows the nest digging as the next step in the sequence of events.