Properties of Plastic

• Strong and ductile
• Poor conductors of heat and electricity
• Easily molded into different shape and size
• Resist corrosion and are resistant to many chemicals.

The distance between seed is important because if seeds are not sown at proper distance there will be a competition between the plants for consuming sunlight,water and space which leads to the improper growth of plants and also damages the whole crop.

Nitrogen cycle is all about the movement of nitrogen between various elements on Earth (like air, soil, living organisms etc.) The amount of nitrogen in the atmosphere remains constant.

• Atmosphere has approx. 78% nitrogen.
• Atmospheric Nitrogen is fixed into the soil
  • N₂ fixing microbes convert atm. N₂ into nitrogen compounds like NH₃
• Plants utilize nitrogen from soil through their roots
• Animals utilize nitrogen, feeding on plants
• When Plants & animals die, Nitrogenous wastes are returned to soil
  • Decomposers convert some part to nitrogen compounds to be used by plants
  • Denitrifying bacteria convert into atm. N₂

• Nitrogen Cycle:

The circulation of nitrogen element through living things and non-living environment is called nitrogen cycle in nature. The main steps involved in nitrogen cycle are:

1. The nitrogen fixing bacteria present in the soil and in the root nodules of leguminous plants, blue-green algae and lightning in the sky fix atmospheric nitrogen and convert it into compounds of nitrogen which go into the soil.
2. The roots of the plants absorb compounds of nitrogen from the soil for their growth and convert them into plant proteins and other organic compounds which make up the body of the plants.
3. The plants are eaten up by animals as food. Animals convert plant proteins into animal proteins and other organic compounds which make up their body.
4. When plants and animals die the complex nitrogen compounds present in their dead bodies are decomposed and converted into simple compounds of nitrogen by certain bacteria and fungi present in the soil.
5. Certain bacteria convert some part of nitrogen compounds into atmospheric nitrogen which goes back into the atmosphere and thus the amount of nitrogen content remains more or less constant.

After Aurangazeb Mughal empire started declining not a single Mughal king who sat on the throne of Delhi was able enough to rule such a big empire conquered by Aurangzeb. Sikhs & Marathas took an advantage of declining Mughal empire. ... Rajput kingdoms in Rajasthan were freed from Mughals. When Aurangzeb died, the empire of the Mughals was the largest in India. Yet, within about fifty years of his death, the Mughal Empire disintegrated. Aurangzeb's death was followed by a war of succession among his three sons. It ended in the victory of the eldest brother, Prince Muazzam.

Hormones are chemical substances that act like messenger molecules in the body. After being made in one part of the body, they travel to other parts of the body where they help control how cells and organs do their work. For example, insulin is a hormone that's made by the beta cells in the pancreas. The main function of endocrine glands is to secrete hormones directly into the bloodstream. Hormones are chemical substances that affect the activity of another part of the body (target site). In essence, hormones serve as messengers, controlling and coordinating activities throughout the body.

Microbes play a vital role in preparing curd from milk. Curd contains a bacterium, Lactobacillus

Lactobacillus is a friendly-bacterium. It treats & prevents diarrhea, helps in food breakdown and absorption of nutrients.

Harvesting is cutting of crop after it is matured. The season of harvesting brings a lot of happiness as this is time when the hard work of farmers brings results.

Harvesting can be done manually using a sickle or with a machine called Harvester.

Atom
An atom can be defined as the smallest constituent particle of an element which showcases independent existence.

Example: Ne, O

 Molecule

A molecule can be defined as the combinations of two or more atoms which are held together by chemical bonds. A molecule is the smallest portion of a substance which showcases all the properties of the substance. On breaking down a molecule further, we see properties of the constituent elements.

Example: O2, HCl

• The growing of crops in the fields for obtaining food is called agriculture.
• The plants of the same kind are grown and cultivated at one place on a large scale is called a crop.
• The crops which are sown in the rainy season are called kharif crops. It is also called as monsoon crops.
• The crops grown in the winter season and harvested in the spring are called rabi crops.
• The activities or tasks done for cultivation of crops involves several activities undertaken by farmers over a period of time are referred as agricultural practices like preparation of soil, sowing, adding manure and fertiliser’s irrigation etc.