Question

need help
Which choice best describes the underlined word or words in each sentence?

For several decades, satellites around the earth have broadcast signals and monitored weather.
complete subject
simple subject
compound subject
none of the above
Which choice best describes the underlined word or words in each sentence?

The ancient Greeks, Hebrews, and Romans left behind important and interesting works of literature and history.
compound subject
simple subject
complete subject
none of the above