Stage is the background appearing when we open the scratch window. The background will most often be white. You can change the background colour as you like.

Palaeontology.

CNS stand for Central Nervous System.

Dolphins, dogs, bats can hear the ultrasonic vibrations.

The total number of atoms present in the molecule is called its atomicity.
\(\text { Atomicity }=\frac{\text { Molecular mass }}{\text { Atomic mass }}\)

When the temperature of a gas is kept constant, the volume of a fixed mass of  gas is inversely proportional to its pressure. \(\mathrm{P} \alpha \frac{1}{\mathrm{~V}}\)

(i) "According to Newton's second law, the force acting on a body is directly proportional to the rate of change of linear momentum of the body and the change in momentum takes place in the direction of the force".
(ii) Force = mass x acceleration
(iii) F = m x a

(i) Transport of respiratory gases (Oxygen and CO₂).
(ii) Transport of digested food materials to the different body cells.
(iii) Transport of hormones.
(iv) Transport of nitrogenous excretory products like ammonia, urea, and uric acid.
(v) It is involved in protection of the body and defense against diseases.
(vi) It acts as buffer and also helps in regulation of pH and body temperature.
(vii) It maintains proper water balance in the body.

(a) Advantages of LED television:
(i) LED television has brighter picture quality
(ii) It is thinner in size
(iii) It uses less power and consumes very less energy.
(iv) Its life span is more.
(v) It is more reliable
(b) Merits of LED bulb:
(i) As there is no filament, there is no loss of energy in the form of heat. It is cooler than the incandescent bulbs
(ii) In comparison with the fluorescent light, the LED bulbs have significantly low power requirement.
(iii) It is not harmful to the environment
(iv) A wide range of colours is possible here.
(v) It is cost-efficient and energy efficient.
(vi) Mercury and other toxic materials are not required.
(vii) One way of overcoming the energy crisis is to use more LED bulbs.

Mass of 1 mole of nitrogen \(\left(N_{2}\right)=2 \times N=2 \times 14=28 \mathrm{~g}\)
Mass of 3 moles of hydrogen \(\left(\mathrm{H}_{2}\right)=3[2 \times \mathrm{H}]\)
=3[2 x 1]=3[2]
=6 g
Mass of 2 moles of ammonia \(\left(\mathrm{NH}_{3}\right)=2\left[\mathrm{NH}_{3}\right]\)
=2[1 x N + 3 x H] 
=2[1 x14 + 3 x 1] 
=2[14 + 3] 
=2[17] = 34 g
\(\left.\begin{array}{c}1 \text { mole of nitrogen }(28 \mathrm{~g}) \\ + \\ 3 \text { mole of hydrogen }(6 \mathrm{~g})\end{array}\right\}=\text {2 moles of ammonia} (34 \mathrm{~g})\)

According to Ohm's law, at a constant temperature, the steady current 'I' flowing through a conductor is directly proportional to the potential difference 'V' between the two ends of the conductor.
\(I\alpha V \Rightarrow\)  V = IR

 Non-Insulin Dependent Diabetes Mellitus.

Body Mass Index

Insulin Dependent Diabetes mellitus.