Air pollution; smoking in the house
Answer:
Rosalind's x-ray showed that the ladders of nucleotides were inside a double helix.
Watson and Crick built models with the ladders on the outside.
The answer is a im pretty sure
Answer:
this is my lazy guess but: human activity, differences in emitted energy from earth, and natural fluctuations. BUT DONT TRUST ME LOOK IT UP IM NOT SMART
