In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.

Q: Lightning can travel _ miles or more horizontally from the storm, then strike the ground.

A: six
****
Q: Females reach sexual maturity around four to _ year-olds.

A: five
****
Q: Cysteine proteinases are important virulence factors, which are encoded by at least _ genes.

A:
six
****