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a person's red blood cells completely lack antigens. this person has blood type

a. a
b. ab
c. b
d. o

i am pretty sure its o but i wanna check just in case

a, b, c - sides of a triangle

a + b > c

a + c > b

b + c > a

we have a = 5m and b = 11m. substitute:

5 + 11 > c

16 > c → c < 16

5 + c > 11         subtract 5 from both sides

c > 6

11 + c > 5         subtract 11 from both sides

c > -6

c < 16 and c > 6 and c > -6

thereofre your answer is 6m < c < 16m

obviously, the latter.