Your answer would be the third option
Answer:
Certain fossils, called index fossils, help geologists match rock layers. To be useful as an index fossil, a fossil must be widely distributed and represent a type of organism that existed for a brief time period. Index fossils are useful because they tell the relative ages of the rock layers in which they occur.
The answer might be gene pool?
Answer:
Diseases is a particular abnormal condition that a negetavile affects the parts of the body system
The different ways we can get a disease are:
. Contaminated air
. Dirty water
.direct or indirect contact with another person who have diseases.
A plant or animal organism that lives In or on another takes the nourishment from that other organism is known as parasite.
Explanation:
<h2> Hope it helps
<u>.</u><u> </u><u /></h2>
<u>Please</u><u> </u><u>give</u><u> </u><u>me</u><u> </u><u>brainliest</u><u> </u><u>answer</u><u>.</u><u> </u>