The
correct answer is they filter urea from blood and produce urine.
<span>
Nitrogenous
wastes tend to form toxic ammonia which needs to be removed. Terrestrial
animals must detoxify ammonia by converting it into a relatively nontoxic molecule-urea
(it occurs in the urea cycle). The urea cycle mainly occurs in the liver and the
produced urea is then released into the blood. It travels to the kidneys where
is filtrated and excreted in urine.</span>
Haiii !! I believe the third option to be reasonable
1 mile.
Since he walks at a speed of 2 miles per hour, he will have only walked 1 mile after walking for half of an hour.
