Do you think a feature of early embryology, such as the fate of the blastopore, is a good basis for classifying animals? Explain your answer. Although they are the most abundant class of echinoderms, comparatively little is known about ophiuroids, Why do you suppose that is the case? In which class of cnidarians is Aristotle's Lantern present? What is its function? How do hemichordates differ from chordates? How is feeding similar in urochordates and cephalochordates? How is it different?

the oxygenated blood then leaves the lungs through pulmonary veins, which return it to the left heart, completing the pulmonary cycle. this blood then enters the left atrium, which pumps it through the mitral valve into the left ventricle. from the left ventricle, the blood passes through the aortic valve to the aorta.

deoxygenated blood leaves through the right ventricle through the pulmonary artery. from the right atrium, the blood is pumped through the tricuspid valve (or right atrioventricular valve), into the right ventricle.

in 1859, charles darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. he defined natural selection as the "principle by which each slight variation [of a trait], if useful, is preserved".

they kick it to the curb.

explanation:

that current was nasty.

the wetland preservation movement began in the u.s. in earnest with the clean water act (cwa) of 1972. although not specifically written to protect wetlands, the cwa is comprised of a series of regulations designed to prevent pollutants from contaminating u.s. waters.