Blood vessel walls contain elastin, a protein that allows the vessel to stretch under high pressure. Which type of blood vessel do you expect will have the highest concentration of elastin in its walls?

What initially causes a nerve impulse? release of enzymes out of the neuron movement of chemicals into the dendrites of the neuron pathogens attacking the dendrites of the neuron red blood cells bathing the neuron

Why has two different alleles for the same trait?

Which of the following is an abiotic factor in an ecosystem? a. bacteriab. airc. niched. grass(abiotic=non-living) me !