class8 science

1. Watering the crops is called:

• (a) sowing

• (b) manuring

• c) tilling

• d) irrigation

2. Weeds are the:

• (a) main crop plants

• (b) insects and pests

• (c) unwanted plants growing along the crop

• (d) chemical substances

3. Combines are used for:

• (a) sowing of seeds

• (b) harvesting the crops

• (c) threshing

• (d) harvesting and threshing both.

Separating grains from chaff is called:

• (a) winnowing

• (b) threshing

• (C)fallow

• (d) harvesting.

Kharif crops are sown in

• (a) March, April

• (b) May, June

• (c) October, November

• (d) Any time.

Friction wears away the treads on a tire after miles of driving.  Physical or chemical change?

• Chemical change
• Physical change

H20 is the symbol for what?

• Sodium
• Potassium
• Hydrogen Peroxide
• Water

Symbol of cacium

• Ca

• K

• La

• Ka

Iron react with cold water

• Yes

• No

Why sodium is kept in kerosene