Biology Past Questions and Answers

The excretory organ in insects is the ____________

Nitrogen-fixing micro-organisms in leguminous plants live symbiotically in the ____________

The blood vessels which carries digested food from the small intestine to the liver is the ____________

The mass number of an atom of an element is sum of its _____________

How many unpaired electrons are there in an atom of an element with the following electronic configuration \(1S^2S^22P^2\)?