Because the molecules that are being transported is moving against its concentration. gradient. in other words, its moving from where it's low in concentration to where it's high in concentration.
The scheme of modern taxonomy goes:
Life > Domain > Kingdom > Phylum > Class > Order > Family > Genus > Species
So, a PHYLUM is made of several classes.
I found the full exercise on the internet and it describes that there are three enzymes and you want to know which are the two enzymes from the <span>digestive tract of the mondoni and which one is the enzyme from a hot spring.
Attached are two graphs from the analysis of the activity of these enzymes regarding temperature and pH. I found these graphs with the full exercise.
The enzymes that probably came from the </span>digestive tract of the mondoni were enzymes A and B. These enzymes were resistant two lower levels of pH which indicates that they could be present in a <span>digestive tract, which tends to be acidic, while the enzyme C does not tolerate lower pH levels. Enzymes A and B were also more active when in lower temperatures that match temperatures of a normal living organism, whereas enzyme C was more active in higher temperatures matching its probable provenience - a hot spring.</span>
Blood vessels visible in the posterior view of the heart include the Superior and inferior vena cava and the pulmonary veins. The superior vena cava and the inferior vena cava drain systemic venous blood into the posterior wall of the right atrium. The pulmonary veins transport blood from the lungs back to the heart and are best seen in posterior view of the heart. Other features visible in the posterior view include, right and left atrium, right and left ventricle, aorta, aortic arch, pulmonary veins and arteries, coronary sinus, coronary artery and posterior interventricular artery.