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.

Q: Niobium occurs primarily in ____ minerals, columbite and pyrochlore.

A: two
****
Q: Calves are spotted when born and develop their brown coats in ____ months.

A: six
****
Q: Chemists use one or ____ lettters to represent elements.

A:
two
****