How fossils form

Question 1

Which statement best describes how a fossil is formed?

Accepted Answer

An organism dies, its remains are quickly covered by mud or sand, and over millions of years the sediment hardens into rock, preserving the shape of the organism as a fossil.

Answer

A living animal hides in a cave, and as the cave walls harden, the animal itself turns into a fossil.

Answer

A dinosaur’s bones are dug up and placed in a museum, and the bones then become fossils.

Answer

A plant falls into a river, the water freezes around it, and the frozen plant becomes a fossil.

Question 2

Sam found a dinosaur bone lying in soft river mud and wonders how it could become a fossil after many millions of years. Which explanation shows the correct steps?

Accepted Answer

The bone is already dead, gets buried in the soft mud, many layers of sand and silt pile on top, and mineral‑rich water moves through the layers turning the mud into solid rock that keeps the bone’s shape.

Answer

The bone stays on the river bank, the sun dries the mud around it, and after a few weeks the bone hardens into stone.

Answer

Animals eat the bone, and the chemicals in their stomachs turn the pieces into a fossil.

Answer

A leaf settles on top of the bone, the leaf changes into rock, and the bone is pulled into the rock at the same time.

Question 3

Which of the following describes the correct sequence of events that leads to the formation of a fossil?

Accepted Answer

The organism dies, its remains are buried in mud or sand, layers of sediment build up over it, and over millions of years the sediment hardens into rock, preserving the shape of the organism as a fossil.

Answer

The organism dies, its body is left on the surface, and rainwater slowly turns the bones into stone without any burial.

Answer

The organism dies, is buried in mud, and the mud later dissolves, leaving the original organism intact as a fossil.

Answer

The organism dies, its bones are immediately turned into rock, and the surrounding soil erodes away, leaving the fossil exposed.

Try three questions

Which statement best describes how a fossil is formed?

Sam found a dinosaur bone lying in soft river mud and wonders how it could become a fossil after many millions of years. Which explanation shows the correct steps?

Which of the following describes the correct sequence of events that leads to the formation of a fossil?

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