EducatorSharmin

Lymphocytes: Q.1. What are lymphocytes? Ans:   Lymphocyte is a type of white blood cell that is involved in the immune response; unlike phagocytes, they become active only in the presence of a particular antigen that 'matches' their specific receptors or antibodies. Biology Q.2. What is B-lymphocyte? Ans: A type of lymphocyte that gives rise to plasma cells and secret antibodies. Q.3. What is T-lymphocyte? Ans: A lymphocyte that does not secret antibodies; T helper lymphocytes stimulate the immune system to respond during an infection, and killer T lymphocytes destroy human cells that are infected with pathogens such as bacteria and viruses. Lymphocytes are the second type of white blood cell. They play an important role in the immune response. Lymphocytes are smaller than phagocytes. They have a large nucleus that fills most of the cell. There are two types of lymphocytes, both of which are produced before birth in the bone marrow. B-lymphocytes (B cells) remain in the bone ...

  Experiment:   Aim:  To observe the miscible and immiscible liquids. Things needed:  Water, oil, milk, 2 spoons, 2 glasses. Method:  a) When milk is mixed in water, they dissolve completely. When two liquids mix together such that they dissolve completely in each other, they are called miscible liquids. b) When oil is mixed in water, it does not dissolve. Instead, oil and water form separate layers within the container. However, when two liquids mix together such that they do not dissolve completely in each other, they are called immiscible liquids. Observation:  We will observe that what happens after 1 hour. Conclusion: Milk and water are mixed but oil and water do not mix. Water Filtration:  Q.3. Give four ways to get safe water from unsafe fresh water.  Ans: The following ways to get safe water from unsafe freshwater- Filtration Sedimentation Boiling Purifying water with chemicals.  Q.5. What are the three states of water?  Ans: The...

Discount: Percentage: Simple Interest Q.1. a scarf priced at $100 is sold for $88. Find the percentage discount. Solution:                     Discount    =  Marked Price - Sale Price                                         =  $100 - $88                                          = $12                        Percentage discount = 12/100  x 100%                                                             = 12% Ans.   Q.2. A laptop is sold for $1274 after a discount of 9%. i) Find the marked price of the ...

Area & Perimeter of Trapezium * A quadrilateral having one pair of parallel sides is called a trapezium. * A figure surrounded by 4 straight lines is called a quadrilateral. * A line segment joining two opposite pairs of vertices is called a diagonal. A quadrilateral has two diagonals, but a triangle does not have any diagonal. * A trapezium is a quadrilateral in which one pair of opposite sides are parallel to each other. In trapezium ABCD, AB॥DC but BC∦AD. A trapezium is not a quadrilateral.                  Area of a trapezium                       = 1/2 x (sum of lengths of parallel sides ) x height                                      = 1/2  (a + b) h * A quadrilateral with one pair of sides parallel is called a trapezium. Suppose that AB = a   and   DC = b...