Prevention of soil pollution:
(i) There should be a ban on polythene bags and plastics.
(ii) Waste products and chemicals should be treated before they are released into the soil.
(iii) The use of pesticides should be minimised.
(iv) Cultivation by natural fertilisers and not using the toxic pesticides and artificial fertilisers.
(v) Avoid dumping of industrial waste, acidic precipitates etc in to the soil.
(vi) avoid using detergents.
(vii) High concentrations of lead, arsenic, nickel, cobalt, and cadmium should be avoided.
(viii) Planting more tree.

A herb is a non-woody plant that has green and tender stem with few branches on. It is usually short. Herbs have a variety of uses like adding flavor to food, providing medicine for diseases and  some with spiritual touch. Tulsi and lettuce are the examples of herbs.
A tree is a woody plant that has many branches on a single stem. Trees serve us lot of benefits. They prevent soil erosion, maintain carbon dioxide content in the air, provide us materials to make huts and to make furniture. Trees are categorized based on their height, width of their trunk, overall size, and of course their age. Mango tree and coconut tree are the examples of trees.

Absorption: The process of passing of digested food into blood vessels in the intestine is called the absorption.
Assimilation: The conversion of absorbed food in complex substances such as proteins and vitamins required by body is called assimilation. In other words, assimilation is the conversion of absorbed food (nutrients) into living tissues. Through the process of assimilation our cells are supplied with oxygen and nutrients.

Concave Mirror:
(i) A concave mirror is a spherical mirror in which the reflecting surface and the center of curvature fall on the same side of the mirror. In other words, if the mirror coating lies outside of the spherical surface, then it is known as a concave mirror.
(ii) Image can be projected on a screen.
(iii) The images formed by the concave mirrors are magnified in nature.               
(iv) The object in the image formed by the concave mirror look bigger than the original size of the object.
(v) Concave mirrors form real and inverted images except when the object is between pole and focus.                

Convex Mirror

(i) A convex mirror is a spherical mirror in which the reflecting surface and the center of curvature lie on the opposite sides of the mirror. In other words, if the mirror coating lies in the inside of the spherical surface, then it is known as a convex mirror.
(ii) Image cannot be projected on a screen.
(iii) The images formed by the convex mirrors are diminished in nature.
(iv) The object in the image formed by the convex mirror look smaller than the original size of the object.
(v) Convex mirrors form virtual and erect images irrespecive of the position of the object.

Rainwater harvesting as the name suggests is the harvesting of rainwater in the sense it is a process involving collection and the storage of rain water using the help of artificially designed systems that runs off natural or man-made catchment areas like the roof top, compounds, rock surface, hill slopes, artificially repaired impervious or semi-pervious land surface. Quite obviously a number of factors play a vital role in the amount of water harvested, some of these factors are the frequency and the quantity of rainfall, catchments characteristics, water demands and the quantum of runoff and above all else the speed and ease with which the rainwater percolates through the subsoil to recharge the ground water.

Water can be classified as soft and hard water based on the type of dissolved salts and behavior with soaps.
(i) Soft water: Soft water lathers easily with soap and contains few or no calcium or magnesium metal. A good example of soft water is rain water.
(ii) Hard water: Hard water  does not produce lather with soap, form scum and cannot be used for laundry. Ex:  River, sea and sometimes even well water.
Hard water is classified into 2 types:
Temporary hard water: A sample water which form scum with soap, but on boiling and then treating with soap produce leather is called temporary hard water.
Permanent hard water: A sample of water which form scum with soap even boiling is called permanent hard water.

Water can be classified as soft and hard water based on the type of dissolved salts and behavior with soaps.
(i) Soft water: Soft water lathers easily with soap and contains few or no calcium or magnesium metal. A good example of soft water is rain water.
(ii) Hard water: Hard water  does not produce lather with soap, form scum and cannot be used for laundry. Ex:  River, sea and sometimes even well water.
Hard water is classified into 2 types:
Temporary hard water: A sample water which form scum with soap, but on boiling and then treating with soap produce leather is called temporary hard water.
Permanent hard water: A sample of water which form scum with soap even boiling is called permanent hard water.

Binary fission is a type of asexual reproduction and the most common form of reproduction in prokaryotes and eukaryotes. It is a method of separating a body into two new bodies. In this, an organism duplicates its genetic material and divides into two parts where every new organism receives one copy of DNA.
It is a primary method of reproduction in prokaryotic organisms. Fission occurs without any spindle apparatus formation in the cell. Here, the single DNA molecule replicates first and then attaches each copy to the cell membrane’s different part. When the cell started to pulls apart, the original and replicated chromosomes get separated.

Difference Between Conductor and Insulator:
(i) Conductors can pass the heat and electricity but the insulators are not capable of doing this.
(ii) The conductors are having the free electrons which are the reason behind their ability to be the conductor. While the insulators are not having the free electrons so they are not having this ability as well.
(iii) Metals are commonly the conductors. While the Non-metals are generally the insulators.
(iv) Conductors are commonly used to make the wires and electrical circuits. While the insulators are used for much more purposes than the conductors, such as electrical wires are coated with the insulator materials.
(v) Examples of the conductors are iron and copper etc. While examples of the insulators are the wood and rubbers etc.

Aerobic respiration:(i) It occurs in the presence of O₂.
(ii) It involves the exchange of gases.
(iii) It occurs in cytoplasm and mitochondria.
(iv) It always releases CO₂ and H₂O.

Anaerobic respiration: (i) It occurs in the absence of O₂.
(ii) Exchange of gases is does not happen.
(iii) It occurs only in cytoplasm.
(iv) End products vary.