To adjust blood pressure independently in the capillaries of the gas-exchange surface and in the capillaries of the general body circulation, an organism would need a(n) .

An organism would need a 4 chambered heart.

Explanation:

The heart consists of 4 chambers in which blood flows freely.  Right atrium, left atrium, left ventricle and right ventricle.

The pulmonary arteries carry de-oxygenated blood to the lungs  from where CO2 is released and O2 is picked up during the process of respiration. The pulmonary vein then takes the oxygenated blood to the left atrium of the heart and then to the left ventricle of the heart.

meteorologists would compare a new weather map with one 24 h old to see how fast a front is moving.

nucleic acid molecules are incredibly complex, containing the code that guarantees the four different nucleotide units comprise dna, the nucleic acid of interest to the genealogist. and one of four nitrogen-containing molecules called nucleotides