Which step is required for better survival of human beings

Air is a mixture of various gases. One of the gases is 21% part of the air and is essential for the survival of human beings. This gas is

'Supervision is required for the survival of organisation." Comment.

Which one value is required for better enzymatic action

List two basic requirements for the survival of life in the biosphere.

List two basic requirements for the survival of life in the biosphere.

Which is not the feature of human being?

Which of the following frequencies is audible to human beings ?