Look at the plant in the picture. It has been sitting on this windowsill for two weeks. Which tropism does its growth show?

A morning glory tendril brushes against a wire fence, and within a few hours it has coiled tightly around the wire. What is this response called?

The pot in the picture was knocked over three days ago and left inside a dark cupboard the whole time. Which tropism produced the growth you can see in the stem?

A maize root is growing through dry soil. It reaches a layer where a leaking pipe has kept the soil damp, and the root turns and grows along that damp layer. Which tropism is this?

Look at the bean plant in the picture. Which stimulus is its stem responding to?

A germinating corn seedling is pinned on its side on damp paper inside a sealed, completely dark box. Two days later, how have the shoot and the root grown?

The seedling in the picture is standing straight, and the lamp beside it will be left on for the next four days while the room stays otherwise dark. What will the shoot have done by then?

A bean seed germinates lying flat, and its first root emerges pointing sideways. As that root keeps growing, which way does it turn, and what is the response called?

The geranium in the picture has been on this windowsill for a month. A student now turns the pot 180 degrees, so the stems lean into the room instead. What happens over the following week?

A seedling is grown in a dark room lit only by a single lamp mounted directly above it. How does the shoot grow, and why?

The seedling in the picture is growing inside this box. The lid will stay shut, and the hole in the side is the only opening. Where does the shoot grow over the next two weeks?

A shoot is lit from its left side only, and light reaches it from nowhere else. How is auxin distributed across the growing region, and what does it do there?

Under a microscope, the cells on the shaded side of a bent shoot are clearly longer than the cells on the lit side. What has the auxin there done to produce that difference?

Look at the seedling in the picture, which has grown like this for three days in a box lit from one side. Where was the auxin that bent its shoot made?

When a root is laid on its side, dense starch grains in the cells of its root cap settle toward the lower side of those cells. This settling is how the root senses which way is down.

A seedling is laid on its side and auxin gathers on the lower side of both the shoot and the root. Why does the shoot then curve upward while the root curves downward?

Two coleoptile tips are cut off and set back on the stumps, one over a block of gelatin and one over an impermeable mica sheet. Lit from one side, the gelatin seedling bends toward the light and the mica one grows straight. What does this show?

Look at the seedlings in the picture. Growing this way is an advantage to them. Why?

Seedlings are lit from one side. Those whose shoot tip is buried under a cap of dark sand grow straight up. Those whose lower stem is buried, with the tip left exposed, bend toward the light. Which region detects the direction of the light?

A coleoptile tip is cut off and left standing on a block of agar. In darkness, the block is then set on one side of the cut stump, and the stump bends away from the side carrying the block. What does this result show?