Answer:
They are examples of erosion by water in different forms
Explanation:
The immune system<span> is made up of a network of cells, tissues, and organs that work together to protect the body. One of the important cells involved are white blood cells, also called leukocytes, which come in two basic types that combine to seek out and destroy disease-causing organisms or substances.</span>
<span>The birth of more offspring than can survive.</span>
Development of breast tissue
I don't know if this helps or not but you would want to know the age of the rock (absolute dating) and from there you will be able to know the age of the fossil and what caused it to die.