The compound noun in the sentence is A. life cycles.
<u>A compound noun is a word formed by two or more words</u>. The first one generally indicates the type of object/person; in other words, it classifies the object or person presented in the second word. Furthermore, compound nouns have a different meaning than the meaning of the two words taken separately.
In this sentence,<u> "life cycles" is a compound noun because it has been formed with the words "life" and "cycles", which are also two nouns.</u> "Life", in this case, is indicating the kind of cycle that the sentence is referring to. In that way,<u> the compound noun "life cycles", defined as the series of stages that a living organism goes through during its whole life, does not have the same meaning than the words "life" and "cycles" taken alone</u>.
