If you will recall from the lesson, an elliptical shaped galaxy is an oval, kind of like an egg. Think about the elliptical versus the spiral. Take a stab at explaining how a spiral over time and due to the effects of gravity, might eventually become an elliptical galaxy. *Remember, gravity is the resultant effect of the gravitational attraction between two masses.

equal distribution i think.

the solute can move "downhill," from regions of higher to lower concentration, relying on the specificity of the protein carrier to pass through the membrane. this process is called passive transport or facilitated diffusion, and does not require energy.

blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. as the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.