autotrophs

It is true that when a candle burns, both physical and chemical changes occur. initially, candle burns to produce heat and light. It is a chemical change because candle burns with the formation of gases. Due to the heat produced, some candles simultaneously melts. This is a physical change as the molten candle wax behaves like original candle.

Since the magnetic effect directly depends on the number of turns of the coil. As, Paheli's coil has more number of turns than Boojho. So, her electromagnet is stronger than Boojho.
So, electromagnet of Paheli attracts more pins as compared to Boojho.

The main function of the following organs are as follows:
(a) Blood vessels These run between the heart and the rest of the body. It helps in the transport of blood between heart and various organs of the body.
(b) Kidney It is called as the 'magic filters'. It helps in the removal of unwanted substances like urea from the blood.
(c) Blood platelets This component of blood helps in blood clotting and prevents the blood loss from the body.
(d) Heart It is a pumping organ which receives blood from the body through veins and pumps it with enough force into the arteries from where it is carried to the various body parts.

There are various reasons for which we should be vigilant about matters related to forests:
(i) A decrease in forest area would lead to an increase in carbon dioxide in air. This will lead to an increase of earth's temperature.
(ii) Soil erosion would occur if there are no forests.
(iii) Floods would occur if there are no forests
(iv) Forests provide shelter and food to the living organisms.

Alimentary canal is a long, muscular coiled tube. It is also known as digestive tract. The alimentary canal with its associated glands constitute the digestive system.
These glands are salivary glands, liver and pancreas.

Untreated excreta contaminates water. It encourages algae bloom in water bodies. The water of such water bodies become unfit for drinking and other household purposes. Such water is also cause of a large number of water borne diseases such as typhoid, cholera, hepatitis and polio, etc.

During heavy exercise, the breathing rate can rise upto 25 times per minute.

When surahis and matkas are baked, the burnt horse dung open up the pores in the soil. So that water percolates out of the matkas or surahis, evaporate and cools the water inside the matka.

A long tube along the neck and the chest is called a food pipe or oesophagus. The swallowed food passes into the food pipe. Food is pushed down by the movement of the wall of the food pipe. It pushed the food towards stomach.

Concave and convex mirrors are the parts of sphere whose one side is polished or silvered. So, they are called spherical mirrors.

Plants take in oxygen and give out carbon dioxide. In the cells, oxygen is used to breakdown glucose into carbon dioxide and water as in other organisms. In plants each part can independently take in oxygen from the air and give out carbon dioxide.
 
Leaves of the plants have tiny pores called stomata for exchange of oxygen and carbon dioxide. Like all other living cells of plants, the root cells also need oxygen to generate energy. Roots take up air from the air spaces present between the soil particles. The stems of some plants have tiny pores called lenticels which help in exchange of gases.

Roots, although underground, possess living cells that require oxygen for respiration and production of energy. They absorb oxygen that is present in the spaces between soil particles. But in waterlogged soils, water occupies the spaces between soil particles and pushes the oxygen out into the atmosphere. Thus, roots are deprived of oxygen and this affects root and plant growth.

We must protect our forest because:
(i) Forests provide us with oxygen.
(ii) They protect soil and provide habitat to a large number of animals.
(iii) Forest help in bringing good rainfall in neighbouring areas.
(iv) They are sources of medicines, timber and many other useful products.

(a) The following precautionary measures while checking the fever through a clinical thermometer are
(i) While reading the clinical thermometer, it should never be held by the bulb.
(ii) The clinical thermometer should be washed properly (before and after use).
(b) The values showed by the elder brother of Pankaj, Vishwas, are concern towards the way of using the clinical thermometer and the importance of money as well.

On decreasing the distance between the object and lens, the size of the image increases, the nature of the lens will be convex type.
If the distance between object and lens is less than the focus of the lens, then it forms a virtual image and this image cannot be obtained on a screen but formed on the same side of the object.