CBSE | NCERT CLASS

Biodiversity refers to all the diverse living organisms like plants, animals and micro-organisms present on earth. Kingdom Plantae: The organisms present in this kingdom are eukaryotic, green autotrophs and multicellular. First they are differentiated on the basis of the plant body they divided on the basis of vascular systems then again divided them on the basis of occurrence of seed and then furthered divided on the basis of seeds are covered or not. Kingdom Plantae divided into five divisions: (1) Thallophyta (2) Bryophyta (3) Pteridophyta (4) Gymnosperms (5) Angiosperms.

A linear equation looks like ax+by+c=0 where x,y are two variables and a, b, c are real numbers (a ≠ 0 and b ≠ 0) Example: 4x + 3y -6 = 0                           0.3x + 0.4y + 2.8 =0                  √ 2x + √ 3y = 0 Pair of Linear Equations in Two Variables: When two linear equations are satisfied by the same pair of values of x and y. Such as,    a ₁ x +b ₁ y + c ₁ = 0                    a₂x + b₂y + c₂ = 0 where a₁,b₁,c₁,a₂,b₂,c₂ are real numbers and a₁² + b₁² ≠ 0       a₂² + b₂² ≠ 0 This pair of linear equations can be solved in two ways: 1. Graphical method 2. Algebric method Linear Equations in Two Variables cbse...

Biodiversity Kingdom Animalia : In this kingdom living organisms are divided into ten groups or phyla. They are porifera, cnidaria, platyhelminthes, nematoda, annelida, arthropoda, mullusca, echinodermata, protochordata, vertebrata.

Periodic Classification of Elements : Periodic Table Reasons for Classification of Elements:  Classified the elements in periodic table because 1. By this process we can study the elements in well organized way. 2. It helps to correlate the properties of the elements with the fundamental properties of all states of matter. 3. We can find out relation between one element to another. In the early stage scientists are attempt to classified the elements on the basis of density, malleability, ductility, metals or non-metals etc. But these entire attempts are not fruitful. In 1815, William Prout said that atomic mass of an element never differs and it forms the truly scientific basis for a satisfactory scheme of classification.