Easy. Answer is oxygen because it says which one was missing before any life was on earth. And in order to have life on earth you need oxygen!
:)
The most numerous cells in the lungs are dust cells, also known by their scientific term of alveolar marcrophages.
These cells are located in any person's lungs and are responsible for keeping your lungs and air pipes clean of any dust particles and other materials that may harm your body. Their role is to destroy any foreign substances, such as bacteria and others.
<em>Answer: D.
the insect touching the trigger hairs</em>
<em>I did the test</em>
Scientists collect information that allows them to make evolutionary connections between organisms. Similar to detective work, scientists must use evidence to uncover the facts. In the case of phylogeny, evolutionary investigations focus on two types of evidence: morphologic (form and function) and genetic.
Answer:
In the Dead Sea, they found that the rate of evaporation peaks during the day just a few hours after solar radiation peaks.
