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: Birds have ____ basic types of feathers.

A: three
****
Q: Owls have ____ toes on each foot, like most birds.

A: four
****
Q: Association neurons connect the previous ____ types of neurons.

A:
two
****