A class of substances known as are used for their medicinal properties.

alkaloids

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polysaccharides

Alkaloids

A class of substances known as alkaloids are used for their medicinal properties.

Explanation:

Alkaloids are small but complex organic substances with at least one nitrogen atom in its ring structure. Hence, they have strong basic properties, and are produced in naturally by some plants.

Examples of alkaloids and their medicinal properties are as follows:

- caffeine, used in certain drug and drinks to stimulate the nervous system

- morphine, used to reduce pain and induce sleep in humans.

- cocaine, nicotine etc

Alkaloids

Explanation:

Alkaloids are organic compounds that are rich in nitrogen which are commonly found in plants though some may be prepared artificially.

Alkaloids helps in protecting plants against pathogens and animals. However they could also be useful in human and veterinary medicine. They have various pharmacological effects. Example of alkaloids include:

Morphine:They can be used to cure and relief pain

Quinine:fight malaria infection

Chelerythrine: fight bacteria .

All these are found in various plants.

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e