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Answer:
A glance of earth taken from space will depict it blue. This blue colour is actually water, the major part of the earth is covered with water. We need water for almost everything, for example- drinking, bathing, cooking etc and therefore we should know about the properties of water. 65 % human body is composed of water. Water is essential for the survival of life on earth. Water is distributed unevenly on the earth’s surface. It forms a major solvent and dissolves almost every polar solute. So let us have a look at its properties.
Physical properties of water : Water is a colourless and tasteless liquid. The molecules of water have extensive hydrogen bonds resulting in unusual properties in the condensed form. This also leads to high melting and boiling points. As compared to other liquids, water has a higher specific heat, thermal conductivity, surface tension, dipole moment etc. These properties form the reason for its significance in the biosphere. Water is an excellent solvent and therefore it helps in the transportation of ions and molecules required for metabolism. It has a high latent heat of vaporization which helps in the regulation of body temperature
Chemical properties of water: Amphoteric nature:
Water can act as both acid and base, which means that it is amphoteric in nature.
Example:
Acidic Behaviour: H2O(l)+NH3(aq) ⇌ H3O+(aq)+NH+4(aq)
Basic Behavior: H2O(l)+H2S(aq) ⇌ H3O+(aq)+HS−(aq)
Redox reactions:
Electropositive elements reduce water to hydrogen molecule. Thus water is a great source of hydrogen. Let us see an example in this case:
2H2O(l)+2Na(s)→2NaOH(aq)+H2(g)
During the process of photosynthesis, water is oxidized to O2. As water can be oxidized and reduced, it is very useful in redox reactions.
Hydrolysis reaction
Water has a very strong hydrating tendency due to its dielectric constant. It dissolves many ionic compounds. Some covalent and ionic compounds can be hydrolyzed in water.
Explanation:
Answer:
The structure that prevents backflow of blood into the left atrium is the mitral valve.
The vessel that carries oxygen-rich blood to tissues is the aorta.
The capillaries receiving blood flow from the left side of the heart are the Systemic capillaries.
The structure that is located anatomically between the aorta and the left ventricle is the Aortic semilunar valve.
Explanation:
The left atrium receives oxygen-rich blood from the pulmonary vein and passes it to the left ventricle. The back-flow of blood from the left ventricle into the left atrium is prevented by mitral which is a bicuspid valve. The vessel that carries oxygen-rich blood to tissues is the aorta.
Aorta receives oxygen-rich blood from the left ventricle and pumps it into its branches to deliver the blood to the body tissues. Systemic capillaries are the blood vessels that obtain the oxygen-rich blood from the left ventricle through the aorta. Systemic capillaries serve as the site for the exchange of gases and nutrients.
The aortic semilunar valve is located Aortic semilunar valve is the half-moon shape valve present between the left ventricle and aorta to prevent the black flow of blood to the left ventricle.
23. centromeres
25. mitosis
27. cancer
29. sister chromatid
31. tissues
