Rhizobium converts atmospheric nitrogen into the soluble form , which can be then taken in by the leguminous plants.However since Rhizobium cannot prepare their own food , it establishes in the roots of the plant and provide them with nutrients. Plants in turn provide it with food and shelter. Thus there exists a symbiotic relationship between the Rhizobium and leguminous plants.

1)Some Plants feed on insects because they grows in a type of soil which is unable to supply Nitrogen(N).so they feed on insects.

2)Most of the pitcher plants have se type of Most of the pitcher plants have some type of lure to attract insects. Many of them have attractively colored, elongated pitchers with nectar. Some species produce scents to attract their prey. The prey that enters the pitcher cannot escape, as the structure has slippery inner surfaces. The trapped prey will eventually drown in the liquid inside the pitcher. The liquid has digestive enzymes (secreted by the plant) that will dissolve the prey gradually.

In some species, the liquid in the pitcher contains bacteria that act on the prey to decompose the latter. Some others have insect larvae, that feed on the trapped insects, and the plant absorbs the excreta of the larvae. These plants share a symbiotic relation with such larvae. Once the prey gets decomposed, the plant extracts amino acids, peptides, phosphates, ammonium, and urea from the solution.

Yes, it is true that bacteria are present in caecum of ruminants. Many bacteria are present in the caecum of cow, which help in the digestion of a nutrient called cellulose which is contained by plants.

Teeth helps to break down food into smaller particles and also mixes it with saliva. Thus teeth helps in ingestion of food and this process would be difficult without teeth.

Digestive system: The system of organs responsible for getting food into and out of the body and for making use of food to keep the body healthy. The digestive system includes the salivary glands, mouth, esophagus, stomach, liver, gallbladder, pancreas, small intestine, colon, and rectum.

Decomposers are essential element of ecosystem as they provide the soil back with the nutrients by decomposing dead.It lead to formation of fossil. Scavengers and decomposers are important as they clean the environment by eating dead and decaying animals and plants and by making the soil fertile. 

Decomposers and scavengers break down dead plants and animals. They also break down the waste (poop) of other organisms. Decomposers are very important for any ecosystem. If they weren't in the ecosystem, the plants would not get essential nutrients, and dead matter and waste would pile up.

Oxidation is the loss of electron in an element. aWhen an element loses an electron it undergoes the oxidation process.

In some cases, oxidation is not desirable as in metals in which it corrodes them materially. When oxidation reaction takes place in food items, it spoils the taste of food. In ponds, The oxidation is considered favorable as it removes the dead material from the ponds.

It is famous for the rust-resistant composition of the metals used in its construction. The pillar weighs over 3,000 kg (7,000 lb) and is thought to have been erected elsewhere, perhaps outside the Udayagiri Caves, and moved to its present location early in the Delhi Sultanate. The pillar was manufactured by the forge welding of pieces of wrought iron . In a report published in the journal Current Science , R. Balasubramaniam of the IIT Kanpur explains how the pillar's resistance to corrosion is due to a passive protective film at the iron-rust interface.

When a copper vessel is exposed to moist air for a long time it develops a green layer on its surface. Copper corrodes by oxidation in which it reacts with oxygen in the air to form copper oxide. Copper oxide then combines with carbon dioxide to make copper carbonate, which gives it a green colour.

Metal surface reacts with oxygen to form metal oxide. Corrosion is the formation of metal oxide when exposed to moist air. Rust is iron oxide. Corrosion occurs in the presence of moisture. For example, when an iron is exposed to moist air, it reacts with oxygen to form rust(Fe2O3.

• Composition: The silk fibre is chiefly composed of 80% of fibroin, which is protein in nature and 20% of sericin, which is otherwise called as silk gum.

• Strength: Silk as a fibre, has good tensile strength, which allows it to withstand great pulling pressure. Silk is the strongest natural fibre and has moderate abrasion resistance. The strength of the thrown yarns is mainly due to the continuous length of the fibre. Spun silk yarn though strong is weaker than thrown silk filament yarns.

• Elasticity: Silk fibre is an elastic fibre and may be stretched from 1/7 to 1/5 of its original length before breaking. It tends to return to its original size but gradually loses little of its elasticity. This would mean that the fabric would be less sagging and less binding resulting in the wearers comfort.

• Resilience: Silk fabrics retain their shape and have moderate resistance to wrinkling. Fabrics that are made from short – staple spun silk have less resilience.

• Drapability: Silk has a liability and suppleness that, aided by its elasticity and resilience, gives it excellent drapability.

Electric field is defined as the electric force per unit charge. The direction of the field is taken to be the direction of the force it would exert on a positive test charge. The electric field is radially outward from a positive charge and radially in toward a negative point charge.

This is because darker colours absorb heat. Lighter colours do not absorb heat and thus we don’t sweat. So in summers we wear lighter clothes so that we don’t feel sweaty and hot . In winters we do the opposite because we want to feel warm and dark colour absorbs heat so that helps us. 

The reaction between an acid and a base to give a salt and water is known as a neutralisation reaction. Acids and bases react with each other to nullify the effect of each other. Let us consider a simple reaction. Take a sample of NaOH which is a base and add drops of dilute HCl.

The reaction will be as follows:

NaOH + HCl→  NaCl + H₂O(l)

Therefore while suffering from acidity it is prescribed to take antacid which are bitter in taste i.e. they are base. And on entering the body the base neutralise the excess acid released into the stomach and convert it into salt and water.

Non-biodegradable items are items that cannot decay or be broken down by living organisms. For instance, water bottles, tin cans, tires and computers are all items that cannot decay in a land fill. They do not react or dissolve easily into the soil.

Silk has a smooth, soft texture that is not slippery, unlike many synthetic fibers. Silk is one of the strongest natural fibers, but it loses up to 20% of its strength when wet. It has a good moisture regain of 11%. Its elasticity is moderate to poor: if elongated even a small amount, it remains stretched.

Fibres which we get from animals are wool, fur, hair, silk. Animal Fibres are used in the world of manufacturing industries. Wool is mainly brought out from the hairs of sheep and goats as like Angora Goats, Kashmiri Goats, etc. Silk are mainly made out from the cocoon of silkworms.

There are seven major classes of nutrients:

1.  Carbohydrates
2.  Fats
3.  Dietary Fiber
4.  Minerals
5.  Proteins
6.  Vitamins
7.  Water

Mushrooms contain no chlorophyll so they are heterotroph and most are considered saprophytes. as they obtain their nutrition from metabolizing non living organic matter.