Which best describes genetic mutations?

What's the waste product of electrons and pyruvate combining in fermentation?  

Cancer cells spread to other parts of the body by entering the bloodstream. which of the following organs could prevent a cancer cell in the bloodstream from spreading, and why? a. the spleen, because it releases lymphocytes into the blood b. the peyer's patches, because they release lymphocytes into the blood c. the lymph nodes, because they release lymph into the blood d. the thymus, because it releases lymph into the blood

How have crops been modified? a.plants have been made more susceptible to pests b.plants have been made resistant to herbicides c.plants have been made more susceptible to herbicides d.plants have been modified to have reduced yield