What do aquatic organisms need to breathe?
A. dissolved nitrogen
B. dissolved oxygen
C. dissolved argon
D. dissolved carbon

What is one benefit of a nonrenewable resource, such as natural gas? a. generate large amounts of electricity b. less expensive overtime c. produces pollution d. will run out eventually

Which of the following particles always has a positive charge? a. electronb. neutron c. proton d. ion

Areal dna molecule consists of thousands of these pairs of nucleotides. what is the pairing arrangement of the nitrogen bases