What is the simlarity of goblet cells and cilia?
a. both moisten the air.
b. both filter the air.
c. both secrete mucus.
d. both diffuse oxygen.

Based on their location in the atmosphere, the layers are able to have their own special characteristics. for example, most weather occurs in the troposphere. what occurs in each of the other layers? (site 1)

Which two criteria must be met before scientist can use radiocarbon dating? explain your answer

As the earth formed, the force of gravity increased due to increased mass. what effect did this increased gravity have on the forming planet?