Back to topics

How can a cactus save nighttime carbon for the day?

A saguaro can take in carbon dioxide at night and store it for use during daylight. This timing is part of CAM, or crassulacean acid metabolism, which separates carbon uptake from later stages of photosynthesis.

4–5 min

Questions you could explore

  • What is stored overnight, and what happens to it in daylight?
  • How can that timing help with water loss?

Start reading

Ready to try your ideas aloud?

Your topic carries over. Record up to 2½ minutes, depending on your plan.

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.

How can a cactus save nighttime carbon for the day? | Speech Topic | speaking.app