Given a sentence with a missing word, pick the answer option that best fills out the missing word in the sentence. Indicate each answer with its index ('a', 'b', 'c', 'd').

Motor neurons are divided into ____ groups.\Question: Choose the right answer from options given a) two b) six c) seven d) eight
a

Women gain ____ years per child they had.\Question: Choose the right answer from options given a) ten b) nine c) four d) two
d

Sexual reproduction requires ____ parents and is genetically variable.\Question: Choose the right answer from options given a) four b) two c) three d) nine

b