What structures in a leaf can open to allow gas exchange during photosynthesis, and can close during hot and dry conditions?

What plant hormone is involved in fruit ripening and stimulating the shedding of leaves, flowers, and fruits?

This is a type of ornamental grass. Is this plant a monocot or a eudicot, and what type of root system does it have?

In this microscopic image of a stem cross section, the vascular bundles are scattered throughout the tissue. Is this characteristic of a monocot or a eudicot? To what group of plants do eudicots and monocots belong?

In all seedless vascular plants, gymnosperms, and bryophytes, the sporophyte is the dominant generation. 

Seedless plants, such as ferns and mosses, must have water for reproduction.

What kind of tropism is this plant exhibiting that causes it to bend as is grows around the pole?

Gymnosperms and angiosperms rely on water for reproduction.

A potato is a swollen tuber that stores starch. What part of plant is a tuber?

Which tissue transports water and minerals within a plant?