D, the independent variable is what you are changing
Answer:
Mosquitoes have thin, long bodies and three pairs of extremely long legs. They have scales along the veins of their wings and long beak-like, sharp sucking mouth parts called a proboscis. These two features distinguish mosquitoes from other flies. Mosquitoes also have feathery or hairy antennae.
The tricuspid valve shuts. This prevents blood from flowing backward into the right atrium while the ventricle contracts. So, your answer will be the Tricuslid Valve. Hope I helped!
