Mechanical waves cannot move without a medium
The answer is "Groundwater"
Initiation, elongation, and termination
Nucleotides are being named or classified by their bases. They are adenine, cytosine, guanine, thymine and uracil. Nucleotides are organic molecules that serve as the monomers, or subunits, of nucleic acids like DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).
Answer:
Oil spill
Explanation:
Its the oil spill because the pollution from it can be traced back to a specific source
