1) How is a manure different from a fertilizer?
2) Name various gases present in air. Give their percentage also.
3) List any three advantages of machines.
4) Give four ways to show how plants are dependent on animals?
Answers
Explanation:
1.
Manure is better than fertiliser. Manure is derived naturally and adds a lot more than just nutrients to the soil. They increase the activity of the microbes in the soil and increase its fertility
2.
The permanent gases whose percentages do not change from day to day are nitrogen, oxygen and argon. Nitrogen accounts for 78% of the atmosphere, oxygen 21% and argon 0.9%. Gases like carbon dioxide, nitrous oxides, methane, and ozone are trace gases that account for about a tenth of one percent of the atmosphere
3.
Machinery is being extensively used because of certain advantages.
The following are the chief advantages of the use of machinery:
Use of Natural Forces:
Heavy and Delicate Work:
Faster Work:
More Accurate Work:
Strain on:
Cheap Goods:
Mobility of Labour
4.
Plants depend on them for carbon dioxide. Carbon dioxide is used by plants for respiration and photosynthesis. ... Some insects and birds are also carriers of pollen grains which are good for development of plants. The animals are the agents of dispersal of seeds which helps the plants to grow.