Why are some polymers elastic?

Releasing the stress allows the kinks, coils and loops to form again, and the rubber returns to its original dimensions. Materials made of long, tangled molecules stretch very easily. Their elastic modulus is very small. They are called elastomers because they are very "elastic" polymers

Polymers are elastic because their strength of recovering their original shape is high having very weak inter-molecular forces and low Young's modulus

Polymer chains are held together in polymers which are elastic materials by very weak intermolecular bonds, which aloow the polymers to stretch in response to macroscopic stresses applied to them. This extreme flexibility in elastic polymers can extend from 5–700%, depending on the specific material. This elasticity is not due to covalent cross-links, but instead for thermodynamic reasons. So we can say that polymers are elastic because they have very weak inter-molecular forces and low Young's modulus.

image result for how many calories of energy will 20 grams of carbohydrates provide in one gram provides 4 calories

consuming the right balance of protein, carbohydrates and fat can you maintain a healthy weight and optimize your energy levels. protein and carbohydrates both contain 4 calories per gram, while fat provides 9 calories per gram.

estuaries are the partially enclosed coastal bodies of brackish water formed at the mouth of sea where river meets an ocean. it is a transition zone between river and sea water so estuaries are influenced to both marine environment such as tides, waves and to riverine such as flow of fresh water and sediments. the mixing of sea and fresh water provide high level of nutrients, making estuaries a high product habitats.

many estuaries suffers degradation from a variety of human activities like erosion from deforestation, overgrazing, overfishing, drainage and eutrophication.

so from the above statement answers will be

1. false as estuaries are formed due to both brackish and freshwater.

2.true, due to high productivity estuaries are breeding ground for many marine species.

3. direct and indirect activities of man that contribute to pollution and deposition of sediments.