Janice lives in an area of Texas that has a large amount of limestone. When she hikes she often finds small fossils. She knows her city uses petroleum to fuel their power and that there are oil reserves nearby. Fossil fuel reserves indicate that at one time, there was a large
that covered the area.

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.

it's diluted or concentrated

in a diluted solution, you can add a lot more solute but in concentrated only a little more can be added