One of the following appeared on the earth with the coming of the plants and was absent in the past
Carbon dioxide
Methane
Ammonia
Oxygen
Assertion : Comparative biochemistry provides a strong evidence in favour of common ancestory of living beings.
Reason : Genetic code is universal.
Which one of the following sequences is true
Phenomenon of industrial melanism demonstrates
First cell produced on earth is
All of the following are the mammals wholly living in water except