Question

which of the following occurs during artificial cross-pollination? the scientist completely controls the transfer of pollen from one flower to the stigma of another. the plants reproduce sexually by self-pollination. a different species of plant is crossed with the original.

Explanation:

• For the option "The plants reproduce sexually by self - pollination": Artificial cross - pollination involves transferring pollen between different flowers (usually of different plants), not self - pollination. Self - pollination is when pollen is transferred within the same flower or between flowers of the same plant without external (artificial) control for cross - species or cross - plant (non - self) transfer. So this option is incorrect.
• For the option "A different species of plant is crossed with the original": In artificial cross - pollination, we usually cross plants of the same species (or closely related species that can produce viable offspring). Crossing different species often results in non - viable or sterile offspring, and it's not the typical case in artificial cross - pollination for breeding purposes (where we want viable and fertile offspring with desired traits). So this option is incorrect.
• For the option "The scientist completely controls the transfer of pollen from one flower to the stigma of another": In artificial cross - pollination, the scientist manually removes pollen from the anther of one flower and transfers it to the stigma of another flower, thus having complete control over the pollen transfer process. This is the defining characteristic of artificial cross - pollination.

Answer:

The scientist completely controls the transfer of pollen from one flower to the stigma of another.