how would you define a human being without using scientifical definitions about chromosomes etc?

Answer 1

Descarte said it best; "I think, therefore I am"

Answer 2

A human being is a species which can walk,talk and bark . He can be selfish or greedy or even donator of money depending upon the situation. He can help , deceive or ditch others as and when he likes it. He has got power to think and store the knowledge in his memory and got emotions, egos and sentiments which are very difficult to predict in advance.