How seeds travel

A plant cannot walk. If every seed fell at the foot of the parent, the seedlings would compete for the same light and water. Dispersal spreads that risk.

Dandelion and thistle seeds carry a parachute of hairs. A light breeze keeps them aloft. Maple and sycamore seeds have a wing and spin as they fall, so they drift away from the trunk.

Carried by air and water

Some pods dry unevenly and suddenly twist, flicking the seeds outward. Gorse and broom do this on a warm day. You can hear the pods snap. The plant is not aiming. The tension in the drying pod does the throw.

Coconuts and some other large seeds float. A tough, airy husk keeps them up so a river or a current can move them. They still need a shore where they can lodge and grow.

Carried by animals

Burrs hook onto fur and clothing and ride until they are pulled off. Berries take another route: an animal eats the fruit and drops the seed later, often with a little manure as fertiliser. The seed coat is built to survive the journey.

Squirrels bury acorns and do not retrieve every one. A forgotten acorn is a planted oak. The animal was storing food. The tree gains a new site.

Carried by air and water

Seeds leave the parent plant by wind, water, animals, or by being flung. The shape of the seed shows which method it uses. A plant cannot walk. If every seed fell at the foot of the parent, the seedlings would compete for the same light and water.

Put those two statements side by side. The first sets the condition. The second says what happens once that condition is met. How seeds travel needs both. Drop the first and the second has nothing to explain. Drop the second and the first is only the scene.

Carried by animals

If every seed fell at the foot of the parent, the seedlings would compete for the same light and water. Dispersal spreads that risk.

The order is the explanation. What the first sentence names has to be there before the result in the second sentence can show up. The piece does not ask you to accept the result first and hunt for a cause afterwards.

A check you can make

Dispersal spreads that risk. Dandelion and thistle seeds carry a parachute of hairs.

A fair check is sequential. Confirm the first statement. Then see whether the second is the result of it, rather than a separate fact parked in the same piece. If the result shows up without the condition, this account does not cover what you are looking at.