Earth can be divided into three main layers: the core, the mantle and the crust. Each of these layers can be further divided into two parts: the inner and outer core, the upper and lower mantle and the continental and oceanic crust. Both the inner and outer core are made up of mostly iron and a little bit of nickel.

Parasites: The plant which lives on or inside another organism and derives the food from it is called as parasite. These plants produce certain special type of roots called as sucking roots which penetrate into the host plant for e.g. Cuscuta plant.

Saprotrophs: Those non-green plants which obtain food from dead or decaying organic matter are called saprotrophs. The saprophytic plants secrete digestive juices on the dead and decaying organic matter and convert it into a solution. They absorb the nutrients from this solution. For e.g. fungi such as mushrooms, bread mould and yeast.

Teeth: Our teeth cut, tear and grind the food before we swallow it. There are four types of teeth in our mouth.

1. Incisors: These are flat and chisel-shaped teeth. They lie in the front of the mouth. There are eight incisor teeth; four in the upper jaw and four in the lower jaw. The incisor teeth are well adapted for cutting and biting of food items.
2. Canines: These are round shaped, sharp and pointed teeth. Canines are well adapted to hold and tear the food. There are four canine teeth found in human.
3. Premolars: There are two premolars on each side of each jaw. Premolars help in crushing and grinding the food. There are 8 premolar teeth in an adult human.
4. Molars: There are two molars on both sides in both the jaws. They have almost a flat surface with small projections. These teeth are meant for fine grinding of food.

The organisms which exhibit saprotrophic mode of nutrition are called as saprotrophs. Saprotrophs obtain their nutrition from dead and decaying organic matter. Saprotrophs secrete digestive juices onto dead and decaying matter to dissolve it and then absorb nutrients from it. Fungi are saprotrophs. Rhizopus, asperigillus, mushrooms are some of the examples of saprotrophs. These are organisms grow and depend on dead and decaying matter.

Health is described as the state of complete physical, mental and social well being. Thus, being healthy means that one feels good physically, has a positive outlook and is able to cope with social and mental pressures without much difficulty.

For maintaining a healthy life cycle, a person needs to have a balanced and varied diet, needs to exercise, live regularly in a proper shelter and get enough sleep. Maintaining a good hygiene also reduces the chances of developing an infection. Our health is affected not only by unbalanced diet but also by disease causing organisms which may be water-borne, air-borne and food-borne.

Health means ability of a person or animal to remain free of illness and injuries.
Health is not only associated with illness, but it also includes factors that affect health like clean drinking water, pollution free environment, healthy food to eat etc.

To determine whether a substance is an acid or a base, count the hydrogens on each substance before and after the reaction. If the number of hydrogens has decreased that substance is the acid (donates hydrogen ions). If the number of hydrogens has increased that substance is the base (accepts hydrogen ions). When a hydrogen ion is released, the solution becomes acidic. When a hydroxide ion is released, the solution becomes basic. Those two special ions determine whether you are looking at an acid or a base. For example, vinegar is also called acetic acid.

Heterotrophic or parasitic nutrition is found in fungi, lichen, amarbel and pitcher plant

No birds are not autotrophs they are hetrotrophs because they get their food from other organisms. Autotrophs prepare their own food by utilizing solar energy, water, and carbon dioxide by the process of photosynthesis. This results in the formation of glucose. Plants like blue-green algae and bacteria such as cyanobacteria are considered to be examples of autotrophs.

Green plants are called autotrophs since they synthesise their own food. The food synthesised by the plants is stored as starch. In photosynthesis solar energy is captured by the pigment called Chlorophyll and use energy of sunlight to make food from inorganic materials like carbon dioxide and water.

The environment is dynamic in nature.

Explanation: The physical and biological environments of an organism interact with each other through transfer of energy and matter. Change in either of the components, biotic or abiotic, causes change in the other. Therefore, the environment is dynamic in nature.

Repeated growing of crops in the same field removes a lot of precious mineral elements, organic matter and other materials from the soil. The deficiency of plant nutrients and organic matter in the soil is made up by adding manures and fertilisers to the soil.

Manure is a natural substance obtained by the decomposition of animal wastes like cow-dung, human wastes and plant residues, which supplies essential elements and humus to the soil and makes it more fertile. The decomposition is carried out by microorganisms. The decomposed animal and plant matter is used as organic manure.

A fertilizer is a salt or an organic compound containing the necessary plant nutrients like nitrogen, phosphorous or potassium, to make the soil more fertile. These have plant nutrients in concentrated form so they provide quick replenishment of plant nutrients in the soil and restore its fertility. The use of fertilisers has helped the farmers to get better yield of crops such as wheat, paddy, rice, etc. 

Processing fibres into wool:

The wool which is used for knitting sweaters and weaving shawls involves following steps:

1. Shearing: The process of removing hair from the body of a sheep in the form of fleece is called shearing. Usually the hairs are removed during the hot weather which enables sheep to survive without their protective coat of hair. The hair provides woolen fibres and than are processed to obtain woolen yarn. Shearing does not hurt the sheep as the upper most layer of skin is dead.
2. Scouring: The process of washing the fleece that removes dust, dirt, dried sweat and grease is called scouring. This process makes the fleece of sheep clean. The scoured fleece is then dried.
3. Sorting:  The process of separating the fleece of a sheep into sections according to the quality of woolen fibres is called sorting.  The hairy skin is sent to a factory where hair of different textures is sorted. The same quality wool obtained from the fleece of large number of sheep is than mixed together.
4. Dyeing: The hair of sheep is white, brown, or black in color. The white woolen fibres obtained by sorting can be dyed in different colors.
5. Combing: This is a process of preparing woolen fibres for spinning the yarn. It is done by using combs having metal teeth.

The gallbladder is a pear-shaped, hollow structure located under the liver and on the right side of the abdomen. The liver secretes bile juice which is stored in a sac called the gallbladder. Bile juice helps in the digestion of fats.

Ingestion: The intake of food is called ingestion. Method of ingestion, i.e. taking of food, varies from one animal to another.

Ingestion

1. Ingestion refers to the intake of food
2. Ingestion takes place through Mouth

Villi are finger-like outgrowths on the inner walls of small intestine. The villi increase the surface area for absorption of the digested food. Each villus has a network of thin and small blood vessels close to its surface. The surface of the villi absorbs the digested food materials. The absorbed substances are transported via the blood vessels to different organs of the body.

Insulators are used in electrical equipment to support and separate electrical conductors without allowing current through themselves. An insulating material used in bulk to wrap electrical cables or other equipment is called insulation. Wood, cloth, glass, mica, and quartz are some good examples of insulators. Insulators are also protectors as they give protection against heat, sound and of course passage of electricity.

Insulators are used in electrical equipment to support and separate electrical conductors without allowing current through themselves. An insulating material used in bulk to wrap electrical cables or other equipment is called insulation. Wood, cloth, glass, mica, and quartz are some good examples of insulators. Insulators are also protectors as they give protection against heat, sound and of course passage of electricity.

Digested food molecules are absorbed in the small intestine. This means that they pass through the wall of the small intestine and into our bloodstream.

Once in the bloodstream, the digested food molecules are carried around the body to where they are needed.