The buildings in seismic zones, where the earthquakes are more likely to occur, should be so designed that they can withstand major tremors.

Yes, when two forces of equal magnitude act in opposite direction, the net force is zero on that body.

In the sun, heat and light are produced by nuclear reactions.

Chlorine is used in water purification plants because chlorine has the ability to kill germs.

The process of transferring the seedings from the nursery to the main field by hand or manually is called seed transplantation.

Water is an important and precious resource. Nowadays it is polluted with many harmful substances such as sewage, toxic chemicals, silt etc. which get mixed with water. Many industries discharge harmful chemicals into rivers and streams. To avoid these situations many compulsory rules must be obeyed as various physical and chemical processes in the sewage treatment plants must be done before discharging sewage into the water bodies. At our individual level we should consciously save water and do not waste it. Reuse and Recycle should be our Mantra.

Because needle tip has very less area of cross-section in comparison to that of our finger and we know that pressure exerted by a force is inversely proportional to the area where it has been applied, so pressure exerted will be more by the needle tip than the finger.

As, we all hear sound through our ears. The moment like eardrum when sound enters in outer part of ear then it travels down a canal at the end of which a thin membrane is stretched tightly which is called the eardrum. It performs an important function. The stretched rubber sheets like eardrum sound vibrations which make the them vibrate (see figure). In this way the eardrum sends vibrations to the inner ear and the signal goes to the brain.

(a) Chromoplasts are the coloured plastids (except green) that give fruit and flower their colour.
(b) Chloroplasts are known as 'kitchen of the cell
(c) No, all plastids are not coloured. Leucoplasts are the colourless plastids.
(d) No, we will not see plastids in an animal cell as it is devoid of plastids.
(e) Rohit is inquisitive, attentive and has love and care towards nature

Fossil fuels will last only for a few hundred years because they are exhaustible natural resources. If consumed at a rate faster than the rate at which these are formed in nature, they will get exhausted very soon.
Once the present stock of these gets exhausted, no new supplies of these fossil fuels will be available to us in the near future because it required millions of years for the conversion of dead organisms into these fuels.

(a) Cholera By maintaining personal hygiene and good sanitation practices.
(b) Typhoid Eating properly cooked food, drinking boiled water and by getting vaccinated against the disease.
(c) Hepatitis-A Drinking boiled water and getting vaccinated against the disease

The disposal of garbage increases the pollution level. It gets so high that the aquatic life cannot survive as the water is not suitable for breathing.

The milk is heated to 70°C for 15 seconds and then suddenly chilled and stored. By doing so, it prevents the growth of microbes. This process was discovered by Louis Pasteur. It is called Pasteurization.

Adolescence is the period of life, in which organisms become reproductively active. In other words, it is the period of attaining reproductive maturity in boys and girls, which starts from 11-13 years and lasts upto 18-19 years in humans.

Millions of years ago, the earth had dense forests in low lying wetland areas. Due to natural processes like flooding and earthquakes, these forests got buried under the soil. As more soil deposited over them, they were compressed. The temperature also rose as they sunk deeper and deeper. Under high pressure and high temperature, dead plants got slowly converted into coal. The process of conversion of dead vegetation into coal is called carbonisation.