Ranger is used for addition, subtraction, multiplication, and division to ten. 

Tux Math is an open source arcade - style video game for learning arithmetic. The main goal is to make learning effective and fun.

Tux Paint is a free drawing program designed for young children. It has a simple, easy-to-use interface, fun sound effects, and an encouraging cartoon mascot which helps guide children as they use the program.

Binomial nomenclature is an universal system of naming organisms. As per this system, each organism has two names like Genus name and Species name.

It is a tool used to classify organisms based on their similarities and differences.

Grouping of living organisms based on their common features is known as classification.

Yes, virus is not an organism.
Teacher's statement is correct, I agree the statement.
Without cell viruses would not able to multiply so it is not a organism.

Lysosomes are the main digestive compartments of the cell. They lyse a cell. So it is called as scavengers of the cell.

Cell membrane is the boundary of animal cell.

Chromatin and nucleolus are the main things of nucleus.

It is a physical change.

It is a chemical change and non periodic change.

It is a exothermic change.

Batteries are a collection of one or more cells.

Electric bulb, geyser, iron box, immersible water heater are the devices that run using heat effect of electric current.

Electric cell is the device used to generate electricity.

SI unit of electrical conductivity is Siemens / meter (S/m)

The kink prevents the mercury from flowing back into the bulb when the thermometer is taken out of the patients mouth.

It is wrong. Clinical thermometer indicates only 35°C to 42°C. So hot water is greater than 42°C. So it is wrong.

Kodaikanal temperature is greater. The different temperature is
-4°C + 3°C = 7°C

Cell, tissue, organ, organ system, organism

Yes, Desalination is a process to remove the salt from the sea water. After desalinating process we will collect water from sea.

i) Temperature variation can change the substance.
ii) Every substance has a melting point. It attain the melting temperature substance can change.

Electrical conductivity is the measure of a material's ability to conduct an electric current. It is commonly represented by the Greek letter σ(sigma). The S.I Unit of electrical conductivity is Siemens/meter(S/m).

Yes, Ramani's statement is correct. I agree Ramani statement. because laboratory thermometer has no kink. When thermometer is taken out from the hot water, the mercury level will fall. We can't measure the correct temperature.

(i) Dry cells are normaly used in small devices such as remote control for T.V., torch, camera and toys.
A dry cells is a portable form of a leclanche cell. It consists of zinc vessel which acts as a negative electrode or anode the vessal contains a moist paste of saw dusts saturated with a solution of ammonium chloride and zinc chloride. The ammonium chloride acts as an electrolyte.
(ii) Electrolytes are substances that become ions in solution and acquire the capacity to conduct electricity.
(iii) The purpose of zinc chloride is to maintain the moistness of the paste being highly hygroscopic. The carbon rod covered with a brass cap is placed in the middle of vessel. It acts as positive electrode or cathode.
(iv) It is surrounded by a closely packed mixture of charcoal and manganese dioxide (MnO₂) in a muslin bag. Here MnO₂ acts as depolarizer. The zinc vessel is sealed at the top with pitch or shellac. A small hole is provided in it to allow the gases formed by the chemical action to escape. The chemical action inside the cell is the same as in leclanche cell

Telephone:
In telephones, a changing magnetic effect causes a thin sheet of metal (diaphragm) to vibrate. The diaphragm is made of a metal that can be attracted to magnets.
1) The diaphragm is attached to spring that is fixed to the earpiece.
2) When a current flows through the wires, the soft - iron bar becomes an electromagnet.
3) The diaphragm becomes attracted to the electromagnet
4) As the person on the other end of the line speaks, his voice cause the current in the circuit to change. This causes the diaphragm in the earpiece to vibrate, producing sound.