8. a common misconception is that the bulk of a plant's material comes from soilor
water. explain where the carbon in sugars actually comes from, citing evidence
from the calvin cycle to support your answer.

a "theory" a suggestion that is not 100 % accurate, or a figure. some people say its a theory because they of all the passed theory's about one subject. it depends sometimes theory might be accurate and sometimes they are.

a- all cells come from pre-existing cells

answer >   yes we do, women; have three holes, urethral opening(pee hole, vagina, and the women pee/girls pee out of the urethra like the men do; only they have a single opening to pee/ejaculate.   (sorry if i'm too forward with this, but this is for a biology class, isn't it? )

hope that !         : )

d. organisms have cells with different shapes and functions.