Respiration in Organisms — Science STD 7 — Question

Paheli wrote a food chain in the following way: frog → eagle → insects → grass → snake The chain is not in the correct order. Help her to write the food chain correctly.

When you keep food items like bread and fruits outside for a long time especially during the rainy season, you will observe a cottony growth on them.
(i) What is this growth called?
(ii) How does the growth take place?

A farmer was unhappy because of his low crop yield, He discussed the problem with an agricultural scientist and realised that the soil of his field was either too acidic or too basic. What remedy would you suggest the farmer to neutralise the soil?

Why is the smoke going up?

Write one similarity and one difference between the nutrition in amoeba and human beings.

Locate the following zones given as boxed items in figure which shows a diagram of soil profile. Topsoil, subsoil, C-horizon, bedrock.

Look at the given reaction.
Hydrochloric acid + Sodium hydroxide (base) → Sodium chloride (salt) + Water
Sodium chloride formed in this reaction remains in solution form. Can we get solid sodium chloride from this solution? Suggest a method (if any).

Name any two effects of electric current.

For setting curd, a small amount of curd is added to warm milk. The microbes present in the curd help in setting if the temperature of the mixture remains approximately between 35°C to 40°C. At places where room temperature remains much below the range, setting of curd becomes difficult. Suggest a way to set curd in such a situation.

Silk yarn of different textures can be prepared. Define the statement.