Why didn't people know about germs or microbes before the mid-1800s?

Which of the following statements regarding anfinsen's denaturing experiments with ribonuclease a (rnase a) are valid? exposing the denatured protein to air oxidation and then dialysis to remove urea restored the protein to its original functionality. removing urea by dialysis and then allowing air oxidation of the denatured protein restored the protein to its original functionality. denaturing the protein with both urea and β-mercaptoethanol yielded an inactive protein. anfinsen concluded that protein folding is determined by its primary sequence.

The diagram illustrates the activity of vesicles during a cellular process.

Spring tides, when the high tides are at their highest and low tides at their lowest. what is it about these positions that causes these high and low tides?