What does HIV stand for? Is AIDS an infectious disease? List any four modes of spreading AIDS.
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.
With the help of suitable diagrams, explain the various steps of budding in Hydra.
The hydra reproduces by the process of budding by the use of regenerative cells. It carries out the process in the follwoing steps:
i. A bud develops as an outgrowth due to repeated cell division at one
specific site.
ii. The buds develop into tiny individuals
iii. When fully mature, these buds detach from the parent body and become new independent individuals.
What is binary fission in organisms? With the help of suitable diagrams, describe the mode of reproduction in Amoeba.