Identify the simple subject in the sentence below:

Six hundred fifty species of birds live in Australia.
Answer choices for the above question
A. Birds
B. Species
C. Australia
D. Six hundred fifty

To identify the simple subject in a sentence, you need to find the noun or pronoun that the sentence is mainly about. In this case, the sentence is about the birds that live in Australia.

The subject usually consists of a single word, a group of words acting as one entity, or a pronoun. In this sentence, the main noun is "species." However, "species" is not the simple subject because it does not describe what the sentence is primarily about.

The simple subject in this sentence is "birds" because it represents what the sentence is mainly focused on. The correct answer is A. Birds.