Las sustancias nitrogenadas producidas por los animales, como resultado de la degradación de proteínas y ácidos nucleídos pueden ser de tres tipos

scientists have discovered that hiv does not cause aids by the virus's direct effect on the host's immune cells, but rather through the cells' lethal influence on one another. researchers from the gladstone institutes have revealed that hiv does not cause aids by the virus's

colors do exist. the color of the sky is actually violet; humans percieve the color of the sky as blue.

the answer is d p: cell, q: organ, r: organ system, s: tissue