The answer to your question is ''ice forming and then melting back into water''
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>
The right answer is surprisingly E.
Quinones, flavoproteins, cytochrome c, and electrons are important elements, essential for the respiratory chain.
Oxygen in respiration plays a role of final acceptor of electrons (and turns into H2O), but there are other final acceptors of electron transport depending on the species (nitrates for Pseudomonas, Sulphites for Clostridium ...). This allows us to classify respiration in two: aerobic respiration (with oxygen) and anaerobic respiration (without oxygen but with another electron end acceptor).
Substitution causes sickle-cell anemia.