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: Most dens are oval shape, six to ____ feet long and about six feet in height and width.

A: nine
****
Q: Light drives the interconversion of ____ forms of phytochroms.

A: two
****
Q: Blood flows in one direction through the four chambers with the aid of the ____ heart valves.

A:
four
****