Crop Production and Management — Science STD 8 — Question

If an object oscillates 20 times in 1 s, what would be its frequency?

Which air pollutant combines with the haemoglobin of our blood?

Two thermocol balls are held close to each other but they move away from each other, when they are released. Name the force which might be responsible for this phenomenon. Explain.

In which age, maximum increase in height takes places?

Name one solid, one liquid and one gas which burn by producing a flame.

Select the correct word from the following list and fill in the blanks. float, water, crop, nutrients, preparation The first step before growing crops is _________ of the soil.

Some natural resources are given below. Classify them into the exhaustible and inexhaustible natural resources.
Air, coal, natural gas, sunlight, petroleum, minerals, forests, oxygen

What is the main difference between physical and chemical change?

Name an antibiotic extracted from fungus (mould). Name the fungus.