What is a heliocentric model?
a)A solar system model that has the Earth in the center
b)A solar system model that has the sun at the center
c)A model that is created using measurements of the sun in the sky at certain times of the day
d)A model where the earth can rotate freely

List two limitations of natural selection

Using meiosis, the sporophyte produces spores that are .

What is the main reason that attitudes are more often revealed in spoken rather than written language? a. in writing, we try to put the "best face" on what we write. b. we speak far more often than we write. c. in writing, we can more easily conceal our attitudes. d. in spoken language, we are often careless in our use of words.