The sequence of one systole followed by one disatole of the heart chambers is termed as 

H.I.V. has ------------ as genetic material.

Moss cotton is

Find out the incorrect statement(s) :

1. All lanthanides are non-radioactive
2. Some actinides form MO2+, MO22+ oxocations
3. The compounds of lanthanides are more basic than that of actinide compounds
4. 5f elements show variable oxidation states like +2,+3,+4,+5,+6 and +7

Which law is called as the law of periods 

When light enters from one medium to another then which characteristic is not changed