Purple Sea Urchin is distinguished by what characteristics? (Pick two) * 10 points
Longer spines on top and smaller flat spines below
Purplish spines are sharp cones above and flattened paddles underneath
Yellowish spines are sharp cones above and flattened paddles underneath
Transparent spines are sharp cones above and flattened paddles underneath

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.

after receiving a stimus, the sensory receptors send(s) signals to the appropriate area of the body.  

the must be sensory neurons.  

hope its .

whats the answer to your question?