• The sac-like structures in a cell surrounded by membrane are called lysosomes.
• They keep the cells clean by digesting and breaking the outside materials like bacteria, food entering the cell or worn-out cell organelles into small pieces.
• They can digest these organic materials due to the presence of strong digestive enzymes that can brreak down organic compounds. Therefore, lysosome is also known as a suicide sac.

The unit of mass is kilogram and the unit of weight is Newton .
Newton is equal to kilogram metre per second square .
It means, N=kgm/s² .

The chemical formula of sodium nitrate is NaNO₃. Its molecular formula is NNaO₃ and its molar mass is 84.9947 g/mol. It is the sodium salt of nitric acid (HNO₃), and hence, is composed of the sodium cation (Na⁺) and nitrate anion (NO₃^-).

There are three states of matter – solid, liquid and gas.

Solid: Matters which have fixed volume and shape are called solids. For example - stone, wood, brick, ice, sugar, salt, coal, etc. All metals are solid except mercury and gallium.
Liquid: Matters which have fixed volume but indefinite shape are called liquids. For example - milk, water, petrol, kerosene, alcohol, oil, etc. Since liquid can flow, it is also called fluid.
Gas: Matters which have indefinite shape and volume are called gases. For example - air, oxygen, hydrogen, nitrogen, carbon-dioxide, etc.

Displacement can be zero even when distance is not zero. Consider two points A and B such that AB = 5 m. When a car travels from A to B and then back from B to A, distance = 5+5 = 10 m. Displacement = Minimum distance between final(B) and initial position(B) = 0. 

Displacement of a body is the change in its position.It is the shortest distance between the initial and final position of the body. So when the initial and final position of the body is same the displacement would be zero.

eg: If you are travelling along a circular track of radius r ,starting from a point A and you reach back at the same point A in some time.The distance travelled will be equal to 2πr (equal to the circumference of the track) . Since the initial and final position are the same the displacement = zero

The following are considered to be matter: chair, air, smell, cold-drink and smell of perfume.

Explanation:

Matter is mass and occupies a space. Matter can be solids, liquids or gases provided they occupy space and have mass. So, chair, air, almonds, smell of perfume and cold drink are all matter. This is because all of these occupy some space and have mass.

In solid state, chair and almonds are matter. Cold drink is matter in liquid state. In gaseous state, the smell of perfume and air matters. For smell, it must be noted that smell is not matter but the smell of some substance is a matter.

Water molecules have atoms arranged far away from each other. So there are much intermolecular spaces between them. When salt/sugar is dissolved in water, the molecules of salt/sugar goes into the these spaces. Thus no water level rise takes place. but as we go on adding salt/sugar, a time comes when no intermolecular spaces are left. This point is called saturation point and the solution is referred to as the saturated solution. Adding extra amount of sugar/salt in after it is saturated, the level will rise. but not before saturation.

- Albert Einstein was the most popular theoretical physicist in 20th century.
- He was born in Germany but later moved to United States because of some political issues.
- He is mostly-known for his Theory of Relativit (E = mc^2 

All animals were working for humans on Monday. But there was as an animal “camel” who was living alone in the desert and was not doing any work. It was for three days, and the camel did not even start his work. Seeing this, the horse with a saddle on its back came to the camel and said, “O camel, O camel come out and trot like us. (The way horses walk is called trot). Camel was a lazy person, he replied “Humph”.

1. Definition

Plasma Membrane is a thin layer, sized 5-10 nm, secures the interior of a cell from extracellular space. 

Cell wall is the rigid outermost layer of a cell, sized 4-20 um. It supports the cell to continue its inner mechanism. In some plants, it consists of three layers.  

1. Presence 

Plasma membrane is present in all kinds of cells. Cell wall is present exclusively in plant, bacteria, fungi, algae cells. 

1. Structure

Plasma membrane is thin and is visible only under an electron microscope. The hard Cell wall is visible through a light microscope. 

1. Composition 

While plasma membrane is made up of lipids, proteins and carbohydrate, Cell wall consists of chitin (fungi), cellulose (plants) and peptidoglycan (bacteria)

1. Type of organism 

Cell wall is non-living and inactive, whereas plasma membrane is living and metabolically active. 

1. Receptors

Another difference between plasma membrane and cell wall is that the former contains receptors; however; the latter one does not contain any receptors. 

1. Nutrition

The former one requires nutrition to survive, but the latter one does not need nutrition, rather deposition from cell organelles. 

1. Texture

Thickness of plasma membrane or cell membrane remains unchanged throughout its life. In case of a cell wall, it grows with time. 

The gravitational force is a force that attracts any two objects with mass. In fact, every object, including you, is pulling on every other object in the entire universe! This is called Newton's Universal Law of Gravitation. Since the gravitational force is inversely proportional to the square of the separation distance between the two interacting objects, more separation distance will result in weaker gravitational forces. So as two objects are separated from each other, the force of gravitational attraction between them also decreases.

The velocity of the ball changes four times.
1 when the player kicks the ball at rest to another player (agent supplying force is the first player)
2. when the other player kicks the ball towards thebgoal (ageny supplying the force is second player)
3. third time when the goal keeper of the opposite team collects it (agent applying force is the goal keeper)
4. fourth time when the goal keeperbkocks the ball towards the player of his own team . ( agent supplying force is again the goal keeper.)

Inertia: Inertia is that property of a body due to which it resists a change in its state of rest or of uniform motion.

The inertia of a body depends on its mass.

If an object has more mass it has more inertia.

Heavier objects have more inertia than lighter objects.

a) A stone has more inertia than a rubber ball of the same size because it has more than a rubber ball of the same size.

b) A train has more inertia than a bicycle because it has more mass than a bicycle.

c) A 5 rupee coin has more inertia than a 1 rupee coin because it has more mass than one rupee coin.

The electronic configuration of Ne= 2, 8
Atom, which forms ion with 3 positive charges, will have electronic configuration as = 2, 5(K,L)
Hence, the given atom is nitrogen.
Mass number = Number of protons + number of neutrons = 7 + 7 = 14
Similarly, atom which forms ion with 3 negative charges, will have electronic configuration as = 2, 8, 3 (K,L,M)
Hence, the given atom is aluminium.
Mass number = Number of protons + number of neutrons
= 13 + 14 = 27

The magnitude of the gravitational force between earth and an object is given by the formula.

M3- that means it has gain 3 electrons

Now M3- have 10 electrons

So M have 10 - 3=7 electrons

Atomic no = no of protons = original no of electrons

So atomic no is 7 which is nitrogen

Atomic mass = no of ( protons + neutrons)

7+7 =14u

Therefore.....

Atomic no. = 7

Atomic mass = 14u

Element = Nitrogen

The SPD government, committed to parliamentary liberal democracy, utilised military force against more radical communist groups, leading to a permanent split between the SPD and the USPD. The SPD was the largest party during the first 13 years of the new Weimar Republic. Social democracy argues that all citizens should be legally entitled to certain social rights. These are made up of universal access to public services such as education, health care, workers' compensation and other services including child care and care for the elderly.