I would say it’s probably B or C
Answer: The immune system
Explanation:
The immune system is a complex network of proteins and cells that defends the body against infection or any invasion. The human defense system in the body is actually made up of entire organs and vessel systems like the lymph vessels. The immune system is made up of organs that control the production and maturation of certain defense cells.
Initially, all living things are subjected to attack from disease causing agents. Even bacteria, so small that more than a million could fit on the head of a pin, have systems to defend against infection by viruses. This kind of protection gets more sophisticated as organisms become more complex.
Answer:
This is because cell walls protect the cells and allow plants to grow to great heights.
Explanation:
Cells walls are made of a cellulose are only found in plant cells.
Answer:
Heart valves or the closure of the mitral and tricuspid atrioventricular (AV) valves at the beginning of ventricular systole and the closure of the aortic valve and pulmonary valve at the end of ventricular systole.
Explanation:
The heart tone “lub,” or S1, is caused by the closure of the mitral and tricuspid atrioventricular (AV) valves at the beginning of ventricular systole.
The heart tone “dub,” or S2 ( a combination of A2 and P2), is caused by the closure of the aortic valve and pulmonary valve at the end of ventricular systole.
Answer:
mass
Explanation:
the chemical formula for water is H20 which means every molecule of water has 2 atoms of hydrogen and one atom of oxygen. Here comes the key part. from the periodic table of elements one sees that one mole of hydrogen atoms weight 1 gram while one mole of oxygen weights 16 grams.
