The change of direction of light because of change of medium is known as Refraction or Refraction of Light. The ray of light changes its direction or phenomenon of refraction takes place because of difference in speed in different media.

The light travels at faster speed in rare medium and at slower speed in denser medium. The nature of media is taken as relative. For example air is a rarer medium than water or glass.

A reaction intermediate or an intermediate is a molecular entity that is formed from the reactants (or preceding intermediates) and reacts further to give the directly observed products of a chemical reaction. Most chemical reactions are stepwise, that is they take more than one elementary step to complete. A catalyst is a species that is present at the beginning of a reaction and reappears at the end. It does not appear in the final equation. An intermediate is not present at the beginning. It forms during the reaction and disappears before the end.

The kidneys in human beings are a part of the system for excretion and its process of the metabolic waste which can eliminate from an organism. In this vertebrates, this becomes primarily carried out by the lungs and kidney and another part of the skin. In this vertebrates, this becomes primarily carried out by the lungs and kidney and another part of the skin. it is a more important process in a major form of life.

The solution used for white washing of the wall is quick lime(CaO).And when this quick lime is mixed with water it gets converted into slaked lime [Ca(OH)2]
and on exposure to the air it finally gets converted into Calcium carbonate[CaCO₃] due to which walls shine...

1.CaO + H₂O -----> Ca(OH)₂
2.Ca(OH)₂ + CO₂ -----> CaCO₃

The process of photosynthesis takes place in the green leaves of a plant. The carbon dioxide gas required for making food is taken by the plant leaves from the air which enters the leaves through tiny pores called stomata. Water required for making food is taken from the soil which is transported to the leaves from the soil through the roots and the stem. The sunlight provides energy required to carry out the chemical reactions involved in the preparation of food. The green pigment called chlorophyll absorbs sunlight energy.

Nuclear energy is generated by nuclear fission process.

When slow moving neutron are made to strike the atom of a heavy element ²⁵³₉₂U, a reaction takes place and this reaction is known as nuclear fission.

Advantages of nuclear energy:

1.  It produces large amount of useful energy from a very small amount of a nuclear fuel.
2. Once the nuclear fuel is loaded into the reactor, the nuclear power plant can go on producing electricity for two to three years at stretch. There is no need of feeding the fuel again and again.
3. It does not produces any harmful gases like CO2 ,CO etc.

Disadvantages of nuclear energy:

1. The waste product of nuclear is very tough to store.
2. Very high cost if installation is required.

Bile is a fluid that is made and released by the liver and stored in the gallbladder. Bile helps with digestion. It breaks down or emulsify fats into fatty acids, which can be taken into the body by the digestive tract. Bile contains mostly cholesterol, bile acids (also called bile salts), and bilirubin (a breakdown product of red blood cells). It also contains water, body salts (such as potassium and sodium), copper and other metals. Thus, option B is correct. Bile does not function in digest fat by enzymatic action, eliminate waste product or regulate process of digestion.

•  The sun is the source of light energy for living things on the Earth. It helps plants to produce their food.
•  The Sun emits different types of electromagnetic radiation including visible light, ultraviolet light, and infrared radiation.
•  Ultraviolet rays (UV rays) are electromagnetic radiation which has the wavelength from 10 nm to 400 nm.
•  They are very harmful rays which lead to wrinkles, skin cancer and other skin-related issues. When the person is exposed to Sunlight for long-term, it damages the genetic material (DNA).
•  The damaged genetic material leads to uncontrolled cell division in the skin. Thus UV rays cause skin cancer.

Regulation is the act of controlling, or a law, rule or order. An example of a regulation is the control over the sale of tobacco. An example of a regulation is a law that prevents alcohol from being sold in certain places. Regulation is the act of controlling, or a law, rule or order. An example of a regulation is the control over the sale of tobacco. An example of a regulation is a law that prevents alcohol from being sold in certain places.