The answer is 100%. Three are observable, but the fourth is just a carrier.
B. Controlling the flow of Blood to the skin seems to make the most sense
<span>D. Temperature and pH can affect how enzymes work.</span> The action of enzymes can be affected by many factors including temperature, pH and ionic strength. Optimum pH differs per enzyme. Enzymes can be destroyed by heat more than the allowed optimum temperature.
1.), missing links
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Since, it has a nervous system, blood vessels, and a long digestive tube is most likely a segmented worm.
<h3>What is a segmented worm?</h3>
Segmented worms have long tube-like bodies that are divided into segments.
They are the simplest organism with a true nervous system and blood contained in vessels.
They have a long digestive tube that runs down the length of the worm's inner body.
They can take in dissolved oxygen from the water through their skin.
Thus, a segmented worm has a nervous system, blood vessels, and a long digestive tube.
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