Answer: Option B. -> Inflammable substance
:
B
The given picture is a warning signal indicating that the substance kept inside the box is a inflammable substance. Substances which have very low ignition temperature and can easily catch fire with a flame are called inflammable substances. Examples of inflammable substances are petrol, diesel, LPG, etc.

Answer: Option D. -> blue
:
D

The outer zone of candle flame is blue in colour. It is where the complete combustion takes place.
 

Answer: Option B. -> Case 2
:
B

In case 2, the empty paper cup reaches its ignition temperature and catches fire. In case 1, the heat supplied to the paper cup is transferred to water in it. So, in the presence of water, the ignition temperature of the paper is not reached. So, the paper would not burn in case 1.

Answer: Option A. -> True
:
A

White phosphorus is highly reactive and has a very low ignition temperature. It spontaneously ignites at about 30 °C in air. So if the room temperature is more than 30 °C, then it would catch fire. 
It burns with a white flame producing clouds of white smoke. It is usually stored under water to prevent exposure to air.

Answer: Option B. -> Asthma
:
B

Suspended particulate matter (SPM) refers to microscopic solid or liquid matter suspended in the Earth's atmosphere. Air pollutants consist of gaseous pollutants, odours, and SPM, (suspended particulate matter) such as dust, fumes, mist, and smoke. The high concentration of these in and near urban areas causes severe pollution to the surroundings. High amount of SPM in air leads to respiratory problems and lung related diseases like asthma.

Answer: Option B. -> it is easily available in the village.
:
A, C, and D

A good fuel is one which burns easily, produces a large amount of heat and does not leave any undesirable substance. 
For centuries, wood was used as domestic and industrial fuel. But now it has been replaced by fuels like LPG. In many rural parts, people still use wood as a fuel because of its easy availability and low cost. However, burning of wood gives a lot of smoke which is very harmful for human beings. It causes respiratory problem. Also calorific value of LPG (55000 KJ/Kg) is larger than the calorific value of wood (18000 KJ/Kg) 

Answer: Option A. -> True
:
A
A certain minimum temperature is required to initiate combustion reaction. This temperature is called ignition temperature.
A type of combustion where an external agent is not required and the material catches fire automatically is called spontaneous combustion. When the ignition temperature is lesser than the room temperature, combustion takes places on its own without the application of any external agent.

Answer: Option B. -> carbon monoxide
:
B
Incomplete combustion takes place when sufficient amount of oxygen is not present. Incomplete combustion of fuels containing carbon like wood, coal, methane, petroleum, etc releases carbon monoxide (CO) gas which is a very poisonous gas.

Answer: Option B. -> partial
:
B

In the middle zone of candle flame, incomplete combustion takes place.

Answer: Option C. -> heat and oxygen
:
C

Water removes heat and cuts off the supply of oxygen when it is used as a fire extinguisher.
Water cools the combustible material so that its temperature is brought below its ignition temperature. This prevents the fire from spreading. Water vapours also surround the combustible material, helping in cutting off the supply of air so that the fire is exhausted. But water cannot be used for fires involving electrical equipment and inflammable substances.