Answer: number 1
Explanation: that is when we could first sustain life because that is when we gained atmosphere and when we could hold carbon and oxogen
A seals flippers has finger bones when a birds wing is just a bone connected to other joints.
When a virus attacks a cell, it kills the cell and the virus multiplies to spread throughout the body
10.Which of the following is a tool that is used by astronomers to study radiation ?
B) A ground based telescope.
11.Which of the following is evidence of earth's revolution ?
D.constellation movement.
12.Which of the following forms of radiation can be shielded by earth atmosphere ?
A.Gamma rays.
Good luck! :)
