Which structures in the diagram are not directly involved in sexual reproduction?
a. stigma and ovary
b. sepal and petal
c. anther and stamen
d. stigma and pollen user: root nodules are associations between bacteria and plant roots responsible for
a. the plant convert necessary carbon dioxide for use.
b. the plant convert necessary oxygen for use.
c. the plant convert the necessary water for use.
d. the plant convert the necessary nitrogen for use.

The correct answer for the question that is being presented above is this one: "b. sepal and petal." The structures in the diagram are not directly involved in sexual reproduction  are the sepal and petal.

The correct answer for the question that is being presented above is this one: "d. helping the plant convert the necessary nitrogen for use." Root nodules are associations between bacteria and plant roots responsible for helping the plant convert the necessary nitrogen for use.