Catastrophism . a. was a philosophy that was first expounded by the early Greeks b. helped man understand the true nature of the forces that shaped the Grand Canyon c. was based upon the belief that Earth was millions of years old d. is a modern term used to describe earthquakes and volcanic activity

Was a philosophy that was first expounded by the early Greeks

Explanation:

The two main theories about the history of Earth are:

1. Catastrophism

2. Uniformitarianism

Georges Cuvier who was a renowned zoologist and naturalist established the world's current understanding of the history of Earth. He was the one who proposed Catastrophism.

Catastrophism

This theory simply connotes that all geologic alterations or change do occur suprisely/suddenly. This principle therefore simply means that the earth is only a few thousand years old, and that the geological features(all features) are caused by large, sudden and catastrophic events or occurrence.

Meanwhile, the theory/principle of Uniformitarianism:

This states that the earth is of billions of years old, and therefore geologic processes is usually at a standstill (stay at the same rate).

the united states has a federal government. the president is the head of the federal government of the united states. however, each state forms its government for administration purposes. the powers of the state governments are exercised within restricted state boundaries. and citizens participate in this government by voting.