Secondary Sex characteristics are the physical features which distinguish male from female
Example:- Voice - In Male - husky voice. 
In Female - shrill voice.

i) Cranium is the part of our skull that encloses the brain.
ii) It is composed of 8 skull bones fixed together.

i) Anode rays travel in straight lines.
ii) Anode rays are made up of material particles.
iii) Anode rays are deflected by electric and magnetic fields.
iv) The properties of anode rays depend upon the nature of the gas taken inside in the discharge tube.
v) The mass of the particle is the same as the atomic mass of the gas taken inside the discharge tube.

Physical properties of Oxygen
(i) Oxygen is a colourless, odorless and tasteless gas
(ii) It is a poor conductor heat and electricity
(iii) Oxygen dissolves readily in cold water
(iv) It is denser than air
(v) It can made into liquid at high pressure and low temperature
(v) It supports combustion.

The path through which electrons flow from one terminal to another terminal of the source is called electric circuit.

Effects of heat:
When heat energy is supplied to any substance, it brings about many changes.
The three important changes are:
(i) Expansion
(ii) Increase in temperature
(ii) Change in state.

Radius of curvature = 20 cm
Focal length (f) =\(\frac { Radius\quad of\quad curvat }{ 2 } \)
=\(\frac { R }{ 2 } =\frac { 20 }{ 2 } \)=10 cm

► Alveoli are the workhouses of respiratory system.
► The exchange of oxygen and carbondioxide takes place in alveoli.
► It takes up oxygen and gives out carbondioxide.

The plant body of algae are called thallus. It means the plant body is not differentiated into root, stem and leaf.

Acetobacter is a genus of bacteria that oxidize ethanol and produce acetic acid.

The conditions required for a chemical reaction to take place: 
1. Physical contact 
2. Solution of reactants 
3. Electricity 
4. Heat 
5. Light 
6. Catalyst

i) When force is exerted on raw rice, it gets grind to form rice flour
ii) When force is exerted on an inflated balloon at different angles, the shape of the balloon gets changed.

32°F