Answer:
Atrioventricular valves.
Explanation:
Heart is the muscular organ of the body and acts as the pumping organ of the body. Human heart is not bigger than the fist and the human heart is divided into four chambers.
Heart murmur may be defined as the swishing sound that are made during the blood flow. This represent the heart problem. The bicuspid valve of heart is atrioventricular valve. The damage in the atrioventricular valve causes the heart murmuring.
Thus, the answer is atrioventricular valves.
Diffusion, facilitated diffusion, osmosis
Answer:
chemicals are dumped into lakes and rivers
Explanation:
all the other choices are results of cutting down trees
Answer:
They have a closed circulatory system.
Explanation:
In an open circulatory system, blood vessels transport all fluids into a cavity. When the animal moves, the blood inside the cavity moves freely around the body in all directions.
Closed circulatory systems are different to open circulatory systems because blood never leaves the blood vessels. Instead, it is transferred from one blood vessel to another continuously without entering a cavity.
