Need the heart is a muscular organ that pumps blood. blood that contains waste materials is brought to the heart by blood vessels. this blood enters the (left atrium, right atrium, right and then moves down. the presence of the (atrioventricular valve, valves in the aorta, valves in the prevents the backflow of blood inside the heart

The phlogiston theory in the 17th century attempted to explain burning. the theory stated that combustable objects contained a material called phlogiston, a substance without mass, color, odor, etc. after objects burned, the objects were dephlogistonated and were then in their true form. the phlogiston theory was accepted until the 18th century, when lavoisier proved that combustion requires a gas that has mass. phlogiston is considered a) to be scientific knowledge b) not to be scientific knowledge c) to be proven by scientific method d) to be accepted in the modern scientific community

Mutations associated with albinism affect proteins involved in synthesis

Which statement about the immune system is false? a. lymphocytes reduce inflammation, b. b cells remember specific pathogens. c. most white blood cells kill bacteria d. white blood cells are made in lymph nodes.