Look at this tell me why do i find things like this

Topographic maps are used to measure a-composition b-movement c-elevation d-texture

Some gamma ray bursts are hypothesized to come from mergers of neutron stars or black holes. if this hypothesis is correct, what else should we in principle be able to detect from such mergers? a. gravitiational waves b. x-ray bursts c. significant disruption of gas thousands of light-years away in the surrounding galaxy d. an "afterglow" of bright visible light, lasting for weeks

Read the article titled "castro resigns." why did the us impose trade sanctions against cuba in 1962?