Each human retina (and you have two, one in each eye) contains 125 million rods and about 6 million cones. Why do you think we have more rods than cones in our retinas? *

  i think you forgot to put the options but if your reffering to this question then your answer will be "b"  a. add "to" to the base form to create an adjective.b. when the subject of a sentence is singular, add "–s" to the base form.c. add "–ed" to irregular base forms to form the past participle.d. do not use a base form with plural subjects