The main topic of the passage is:

A. The Vaporization of a Meteor

B. The Earth’s Atmosphere

C. Meteor and Meteorite

D. Scientists’ concern: The Cosmic Material

The example in the last paragraph suggests that in the situation described in the italicized lines, tin infant would most likely:

A. understand his mother’s communication stream

B. absorb many of the nuances of his mother’s speech

C. be able to distinguish between his mother’s voice from that of the newscaster

D. separate out his mother’s speech from most of the background noises

The author uses the word “necessarily” in order to suggest that:

A. it is inevitable that two streams of speech are more confusing than one

B. even adults can have trouble distinguishing between streams of equal volume

C. infants always combine separate streams into a single sound

D. an individual stream understandably changes character when mixed with another

The phrase “predicated upon several specific conditions” is used by the author to suggest that:

A. most infants have trouble separating out simultaneous streams of speech only in rare instances do these required conditions occur

B. an infant’s language acquisition ability is entirely dependent upon his environment

C. infants are not always able to learn from their surrounding environment