Matter changes from one state to another when matter it is either heated or cooled and the energy within the matter increases. When a solid changes to gas form, the intermolecular force of attraction decreases and the distance between the molecules increases. The closeness, arrangement and motion of the particles in a substance change when it changes state. When a substance is heated, its internal energy increases: the movement of its particles increases. bonds between particles break when a substance melts or evaporates, or sublimes to form a gas from a solid.

The rate of change of momentum of an object is directly proportional to the resultant force applied and is in the direction of the resultant force. The resultant force is equal to the rate of change of momentum. Newton's second law of motion pertains to the behavior of objects for which all existing forces are not balanced. The second law states that the acceleration of an object is dependent upon two variables - the net force acting upon the object and the mass of the object. The second law of motion states that acceleration is produced when an unbalanced force acts on an object (mass). Examples of Newton's 2nd Law  If you use the same force to push a truck and push a car, the car will have more acceleration than the truck, because the car has less mass.

Muscles provide the tug on the bones needed to bend, straighten, and support joints. Muscles can pull on bones, but they can't push them back to their original position, so the muscles work in pairs of flexors and extensors. The extensor muscle relaxes and stretches as the flexor muscle contracts to bend the joint. Muscle is also very important to everyone because we need our muscles to survive. The heart is the strongest muscle in our body and is always looking to get stronger. Muscles enable us to be active and exercise. ... Aerobic exercise is where repetitive activity and large muscle movement is helping our muscles use oxygen.

Tissues are groups of cells that have a similar structure and act together to perform a specific function. The word tissue comes from a form of an old French verb meaning “to weave”. There are four different types of tissues in animals: connective, muscle, nervous, and epithelial. There are four types of tissues found in animals: epithelial tissue, connective tissue, muscle tissue, and nervous tissue.

• Cell is an autonomous self-replicating structure that forms the structural, functional and biological unit of all living organisms.

• A cell characterized by the absence of a distinct, membrane-bound nucleus or membrane-bound organelles, and by DNA that is not organized into chromosomes is called a prokaryotic cell.

In multicellular organisms, several cells are grouped to form tissues. These tissues perform particular function at a definite place in the body. For example, nerve cells from the nervous tissue which helps in transmission of messages. This is known as division of labour in multicellular organisms. In unicellular organisms, a single cell performs all the basic functions such as respiration, movement, excretion, digestion, etc. But in multicellular organisms, cells are grouped to form tissues. These tissues are specialised to carry out a particular function at a definite place in the body.

When a leaf is examined under the microscope, we observe many tiny pores, which are collectively called stomata.

Stomata are the minute openings, generally found in the epidermis of leaves. They are typically found in plant leaves and can also be found in stems and other parts of plants.  Stomata play an important role by permitting the movement of gases such as oxygen, carbon dioxide, and water vapour to diffuse between the interior and outer surface of the plant tissues.

The main functions of stomata are:

1. Helps in the exchange of gases by opening and closing the pores in the leaves.
2. It helps to expel the excess water out from the leaves in the form of water vapour.
3. Based on the weather conditions, it closes or opens its pores to maintain the moisture balance.
4. Allows the uptake of carbon dioxide and to give out oxygen during the process of photosynthesis.
5. Stomata remain open during the day and closed at night. This closure prevents water from escaping through open pores.

Iodine is used in staining cells of an onion peel on the slide due to following reason.
*Onion bulb is made up of scaly leaves which store starch granules in their cytoplasm of the cells.
*Iodine binds to starch in the granules and develops blue black colour.
*This procedure of staining onion cells with iodine make the onion cells visible clearly. It also confirms the fact that onion stores reserve food material in the form of starch.

An onion is made of layers, each separated by a thin skin or membrane. In this exercise you will make a wet mount on a microscope slide and look at the cells of the onion membrane magnified by the high power, compound microscope. 

To Prepare Stained Temporary Mount of Onion Peel

Peel off a leaf from half a piece of onion and using the forceps, pull out a piece of transparent onion peel (epidermis) from the leaf. Put the epidermis in the watch glass containing distilled water.

Golgi bodies are an arrangement of few fluid-filled dishes whereas Endoplasmic reticulum is a network of tubules and vesicles. Golgi apparatus sorts, modifies, and delivers the components in a cell, whereas Endoplasmic reticulum is much a structurally aiding organelle for metabolic activities. Ribosomes, the endoplasmic reticulum and the Golgi apparatus are related to each other through their involvement in protein synthesis and transport. ... The primary role of the Golgi apparatus is to modify the proteins and encase them into vesicles. From here they are transported to the various parts of the cell.

According to Newton's third law for every action there is equal and opposite reaction.
Action= -reaction
Action and reaction forces do not act on same body[ they act on two different objects].so they do not cancel each other.
For example : the rocket works on principle of action and reaction
Action is force on gases.[ hot gases produced due to rapid burning of fuel]
reaction force is force on rocket.[downward gases pushes rocket upwards]

Intermolecular forces are the forces of attraction between the molecules of a gas.
The strength of the intermolecular forces is affected by change in temperature and pressure.
High pressure brings the molecules of a gas together and hence increases the strength of the intermolecular forces.
As the pressure increases the molecules of the gas come closer together and finally form a liquid.

Digestion of carbohydrates, fats and proteins:

(i) Carbohydrates - The digestion of carbohydrates begins in the mouth. The human saliva contains an enzyme called salivary amylase which digests the starch present in the food into maltose sugar. The slightly digested carbohydrates when reaches the small intestine, pancreatic amylase present in the pancreatic juice breaks down the starch. The intestinal juice of the small intestine completes the digestion of carbohydrates and finally coverts it into glucose.

(ii) Fats - The process of digestion of fats begins in the stomach. The glands of stomach secrete a small amount of gastric lipase that breaks down the fats present in the food. From the stomach the partially digested food goes into small intestine where the pancreatic lipase breaks down the emulsified fats. The walls of small intestine secrete intestinal juice which converts the fats into fatty acids and glycerol.

(iii) Proteins - The digestion of proteins begins in the stomach. The glands of the stomach secrete gastric juice which contains an enzyme called pepsin. Pepsin converts the proteins into peptones. Pancreatic juice contains trypsin which digests the proteins into peptides and the intestinal juice completes the process of digestion of proteins thus converting it into amino acids.

Aqua regia (Latin: royal water) is a mixture of nitric acid(HNO₃) + maximum concentrated hydrochloric acid (33%) in a volume ratio of 1:3 respectively.
As it can dissove royall metals Or noble metals i.e. gold and platinum it is called royal water.