Given a sentence, fill out the missing word with a 'no' or a number (between zero and ten). You should write the numbers with english alphabet, like: four instead of 4.
--------
Question: Avian kidneys have ____ kinds of nephrons.

Answer: two


Question: Most solenoids have ____ tabs with holes for mounting.

Answer: two


Question: Energy is recognised in ____ forms, kinetic and potential.

Answer:
two