A pole star or polar star is a star, preferably bright, nearly aligned with the axis of a rotating astronomical body. The North Star or Pole Star – aka Polaris – is famous for holding nearly still in our sky while the entire northern sky moves around it. That's because it's located nearly at the north celestial pole, the point around which the entire northern sky turns. Polaris marks the way due north.

Boiling is an unnatural process where the liquid gets heated up and vapourized due to continuous heating of the liquid. Evaporation usually occurs on the surface of the liquid being heated up. Boiling usually occurs on the entire mass of the liquid that gets heated up. Bubbling effect is not visible in Evaporation.

Distance and time are base quantity of physics . Take an example to understand what is the difference  between base quantity and derived quantity .

Base quantity is independent quantity like mass ,time distance ect

Derived quantity is depended quantity like force , pressure ect

Golgi apparatus

• The stacks of flattened membranous vesicles are called Golgi apparatus.
• It basically stores, packs and modifies the products in vesicles.
• It temporarily stores protein that moves out of the cell through the vesicles of the Golgi apparatus.
• It packs and transports the materials synthesised in Endoplasmic Reticulum to different targets inside and outside the cell.

n 1920, Indian physicist Satyendra Nath Bose made a study regarding the fifth state of matter. Based on his study, Albert Einstein predicted a fifth state of matter called as the Bose-Einstein Condensate.
The Bose-Einstein condensation or BEC is formed by cooling a gas of extremely low density, about one hundred thousandth of the density of normal air, to super low temperatures.

Golgi apparatus

• The stacks of flattened membranous vesicles are called Golgi apparatus.
• It basically stores, packs and modifies the products in vesicles.
• It temporarily stores protein that moves out of the cell through the vesicles of the Golgi apparatus.
• It packs and transports the materials synthesised in Endoplasmic Reticulum to different targets inside and outside the cell.

Division of labour in multicellular organisms -

•     Multicellular organisms are made of more than one cell.
•     Each cell of their body carries out specific function.
•     Various functions of the body are carried out by different tissues or rather organ systems.
•     As each cell is assigned with its specific task, it is said that labour is divided in multicellular organisms.

An object is said to be in motion if it changes its position with respect time and observer.
An object is said to be at rest if it does not changes its position with respect time and observer.
MOTION AND REST ARE RELATIVE TERMS.
That means it all depends upon the observer who is observing the object.
Example:
1. A person standing in a moving bus is at rest with respect to bus and is in motion with respect to observer on the ground.
2. A girl swinging in garden is in motion with respect to persons moving in garden and at rest with respect to swing.

• The Solid State:

Properties of solids:

1. Solids have a fixed shape and a fixed volume.
2. Solids cannot be compressed much.
3. Solids have high densities. They are heavy.
4. Solids do not fill their container completely.
5. Solids do not flow.

• The Liquid State:

Properties of liquids:

1. Liquids have a fixed volume but they have no fixed shape.
2. Like solids, liquids cannot be compressed much.
3. Liquids have moderate to high densities. They are usually less dense than solids.
4. They do not fill their container completely.
5. They generally flow easily.

The Gaseous State: Properties of gases:

Gases have neither a fixed shape nor a fixed volume.

They can be compressed easily.

They have low densities.

They fill their container completely.

They flow easily.

The characteristic amount of energy absorbed or released by a substance during a change in its physical state that occurs without changing its temperature is known as latent heat. ⭕The two types of latent heat are Latent heat of fusion and latent heat of vapourization.

• We get the smell of our favourite food sitting in the drawing room even when the food is being cooked in kitchen. The vapor coming out from the food reaches to us because of diffusion in air and we get the smell of food.
• We get the smell of burning incense stick sitting far from it. When an incense stick is burnt, the incense present in it vaporizes because of heat. The vapor coming out from the incense stick mixes with air and reaches to us.
• In similar way we sense the good or bad smell from a distance.
• When sugar is added in water, it is mixed because of the diffusion. The particles of sugar collide with the particles of water because of their continuous movement. And finally they are mixed together because of diffusion.
• Carbonated drinks are prepared by the diffusion of gas in water. We notice a hiss sound when the cap of bottle of a carbonated drink is open, the hiss sound comes because of the diffused gas coming out of water. Soda, Soft drinks (coca-cola) etc. are the carbonated drinks and prepared mainly because of the diffusion of carbon dioxide in water.
• Aquatic animals take dissolved oxygen in water while breathing. Aquatic plants synthesize their food under water because of the dissolved carbon dioxide in water. These gases dissolved in water because of the diffusion.

According  to  the  law  of  conservation  of  momentum, the  sum  of  momenta  of two objects  before collision is equal to the sum of momenta after collision, provided there is no external unbalanced force acting on the objects.

Suppose two balls A and B, of masses m_A and m_B are travelling in the same direction along a straight line at different velocities u_A and u_B. And there are no other external unbalanced forces acting on them. Let u_A > u_B and the two balls collide with each other. During collision which lasts for a time t, the ball A exerts a force F_AB on ball B and the ball B exerts a force F_BA  on ball A.

Suppose v_A  and v_B are the velocities of the two balls A and B after the collision, respectively.

The momenta of ball A before and after the collision are m_A u_A and m_A v_A. The rate of change of its momentum (or F_AB, action) during the collision will be

m_A (v_A - u_A)/t

Similarly, the rate of change of momentum of ball B (= F_BA or reaction) during the collision will be

m_B (v_B - u_B)/t.

According to the third law of motion, the force F_AB  exerted by ball A on ball B (action) and the force F_BA  exerted by the ball B on ball A (reaction) must be equal and opposite to each other. Therefore,

F_AB = – F_BA

or

m_A (v_A - u_A)/t = -m_B (v_B - u_B)/t. This gives,

m_A u_A + m_B u_B = m_A u_A + m_B v_B

where m_A and m_B are masses of the bodies, u₁ and u₂ are initial velocities of the bodies and v₁ and v₂ are final velocities of the bodies.

• Consist of live unspecialized cells having thin cell wall.
• They are loosely packed and have large intercellular space (space between the cells).
• Provides support to the plant and present in all parts like roots, stems, leaves, fruits and seeds.
• Storage of food (eg. Fruits) and water (in stems eg. cactus) is the main function.
• Sometimes, these tissues also contain chlorophyll and perform photosynthesis, and known as chlorenchyma.
• In case of aquatic plants, parenchyma is modified into aerenchyma.
• Aerenchyma is the tissues having large air cavities which provides buoyancy to the plants and help them to float.

Displacement is defined as the change in position of an object. It is a vector quantity and has a direction and magnitude. It is represented as an arrow that points from the starting position to the final position. For Example- If an object moves from A position to B, then the object’s position changes. This change in position of an object is known as Displacement.

It is a chemical reaction in which you mix two solutions of two ionic substances and a solid ionic substance (a precipitate) forms.

For example, precipitation occurs when a part of the atmosphere saturates itself with water vapour and when the right temperature comes its condenses and precipitates. The two processes which make the air saturated are the cooling of air molecules and the addition of water vapour.