Pls help! Will mark brainliest!

To be considered they must have lived over a very short period of time and had to be many of them.

A) An index fossil
B) A trace fossil
C) A petrified fossil
D) A carbon fossil

A) Index Fossils

Explanation:

Index fossils are fossils used to define and identify geologic periods. Index fossils must have a short vertical range, wide geographic distribution and rapid evolutionary trends.

organisms are more likely to be more preserved in mud than sand because mud is moist and wet, while sand is very dry.

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e