Before photosynthesis evolved, ___ was rare in earths atmospherer

Which reproductive organ has the greatest number of different functions? A. Ejaculatory duct B. Vagina O C. Vas deferens D. Ovary

Lipids are ___ molecules because they have no negative and positive poles

Why does water roll off the surface of a leaf? A. Because water is attracted to nonpolar molecules B. Because water is a nonpolar molecule C. Because plants do not contain cellulose D. Because the leaf is coated in lipid molecules

On which of the following objects will earth exert a greater gravitational pull than on a pencil?

What are the 4 nitrogen bases and how are they paired in dna?

Why does a temperature inversion trap smog and prevent it from dispersing

Turgor pressure is the result of: A) the activity of the contractile vacuole. B) water accumulation within a cell. C) the rigidity of the plasma membrane. D) All of these choices are correct.

Which activities are ways to reduce the negative impacts humans have on Earths resources? Select two options

How many levels of classification do we use today?

Which statement describes an operon? heritable changes in gene expression that occur without altering the DNA sequence the processing of exons in mRNA that results in a single gene coding for multiple proteins a gene cluster controlled by a single