Which of the following would NOT be considered evidence of past earth events that could help us determine when those events happened? A.
layers of rock that show a volcanic eruption wiped out most life 250 million years ago

B.
finding a shell fossil in limestone

C.
find a trilobite fossil in a 250 million-year-old rock below a 165 million-year-old dinosaur fossil

D.
determining mammals appeared on earth 240 million years ago

The answer is option D "determining mammals appeared on earth 240 million years ago"

Explanation:

Regardless of appearing to be a generally steady spot, the World's surface has changed significantly over the past 4.6 billion years. Mountains have been constructed and dissolved, mainlands and seas have moved significant stretches, and the Earth has varied from being incredibly cold and totally covered with ice to being warm and without ice. These progressions commonly happen so gradually that they are scarcely distinguishable over the range of a human existence, yet even at right now, the World's surface is moving and evolving. As these progressions have happened, creatures have advanced, and remainders of some have been safeguarded as fossils.

the first phase of the government’s plan for settlement was building the transcontinental railroad. the railroad provided a way to bring settlers and manufactured goods west and ship their agricultural and mining produce east. the transcontinental railroad was an essential artery for rapid development of the frontier.

the second phase of the government’s plan was a liberal land distribution policy that made it possible for many people to homestead. with these two key elements—transportation and cheap land—the government rapidly achieved its goal of persuading people to move west, settle on farms, and push back the frontier.