What is the topic of the man’s speech

A．They have a background of respect for education.
B．These subjects require less knowledge of English.
C．They are highly motivated and want to make more money.
D．They work hard in order to improve their life.

A．We can't use different organisms as effectively as our ancestors did.
B．Biotechnology has done harm to the human being since prehistoric times.
C．Biotechnology can be used to modify human health and human environment.
D．Human therapeutic drugs are only dreams of human beings.