Veins have a much lower blood pressure than arteries. what prevents backflow of blood in veins?

Chlorophyll is found in plant leaves and absorbs light from the sun to enable plants to perform photosynthesis. magnesium is an important component of chlorophyll. the concentration of magnesium ions is higher in the root-hair cells of plants than in the soil. which mechanism of ion uptake would best enable a plant to produce a steady supply of chlorophyll? osmosis diffusion passive transport active transport

Plsss > .< compare and contrast the characteristics of flatworms rounds worms and earthworms

Moving down the ramp from 6 meters to