Experiment on Saliva and Starch; Oral Hygiene and Process of Digestion — task. Biology CBSE Live product, Class 7 (2025-26).

Assertion and Reason:

1. Assertion: The blue-black colour appears when iodine is added to test tube A.

Reason: Saliva contains hydrochloric acid, which reacts with starch to give a blue-black colour.

Both assertion and reason are true, and reason explains assertion
Both assertion and reason are true, but reason does not explain assertion.
Assertion is true, but reason is false
Assertion is false, but reason is true

2. Assertion: Villi decrease the surface area for nutrient digestion in the small intestine.

Reason: Villi are long and finger-like projections inside the large intestine.

Both assertion and reason are true, and the reason explains the assertion
Both assertion and reason are true, but the reason does not explain the assertion
Assertion is true, but reason is false
Both assertion and reason are false

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8. Experiment on Saliva and Starch; Oral Hygiene and Process of Digestion

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