What does HIV stand for? Is AIDS an infectious disease? List any four modes of spreading AIDS.
HIV stands for Human Immunodeficiency Virus. It is the virus responsible for the disease AIDS.
Yes, AIDS is an infectious disease.
The four modes of spreading AIDS are:
i. Sexual intercourse with an infected person.
ii. Use of infected needles or syringe.
iii. Transfusion of blood from an infected person to a healthy person.
iv. From a infected pregnant mother to the child during pregnancy, birth and breasfeeding.
Describe any three ways in which individuals with a particular trait may increase in population.
a) State two properties of carbon which lead to a very large number of carbon compounds.
b) Why does micelle formation take place when soap is added to water? why are micelles not formed when soap is added to ethanol ?
Or
Explain isomerism. State any four characteristics of isomers. Draw the structure of possible isomers of butane C4H10.
a) What is meant by the 'power of a lens'?
b) State and define the S.I. unit of power of a lens.
c) A convex lens of focal length 25 cm and a concave lens of focal length 10 cm are placed in close contact with each other.
Calculate the lens power of this combination.
What is binary fission in organisms? With the help of suitable diagrams, describe the mode of reproduction in Amoeba.