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Why do some plant roots house bacteria?

The small nodules on a legume’s roots can contain bacteria that help the plant obtain nitrogen. These bacteria convert atmospheric nitrogen into forms available within the association. The partnership depends on the plant, the bacteria, and growing conditions; a visible nodule alone does not tell you how effective it is.

4–5 min

Questions you could explore

  • What can the plant and the bacteria each gain from the association?

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Nature and biology

How does a honey bee dance give directions?

A returning honey bee can communicate about food without leading every other bee to it. The direction and duration of its waggle dance carry information that other bees can use beyond the dark hive.

3–5 min

How does a honey bee dance give directions?

Nature and biology3–5 minA returning honey bee can communicate about food without leading every other bee to it. The direction and duration of its waggle dance carry information that other bees can use beyond the dark hive.

Nature and biology

How can an octopus change color so quickly?

An octopus can alter the appearance of its skin far faster than a new coat of pigment could grow. Tiny structures already in the skin control what becomes visible, with pigment and reflected light playing different roles.

5–7 min

How can an octopus change color so quickly?

Nature and biology5–7 minAn octopus can alter the appearance of its skin far faster than a new coat of pigment could grow. Tiny structures already in the skin control what becomes visible, with pigment and reflected light playing different roles.

Nature and biology

How do bats use echoes to find prey?

An echo can tell an echolocating bat more than whether something is nearby. The delay and character of returning sound help it follow a target as the encounter changes.

3–5 min

How do bats use echoes to find prey?

Nature and biology3–5 minAn echo can tell an echolocating bat more than whether something is nearby. The delay and character of returning sound help it follow a target as the encounter changes.

Why do some plant roots house bacteria? | Speech Topic | speaking.app