A) the importance of size and interesting eating habits of blue whales.
Answer:
Gerund.
Explanation:
A gerund is a form of a verb when the actions is not yet finished. It main difference from the other verbs is that it ends with "ing". Often, but not exclusively, it functions as a noun. Which means that can receive and perform an action. But it also retains properties of a verb, like being modificable by an adverb.
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