Consider the following:

How many of the above have poisonous species among them?

(a) Only one
(b) Only two
(c) All three
(d) None

The correct answer is (c) All three.

Explanation:

Butterflies:
- Many butterflies are poisonous. They ingest toxic chemicals from their host plants as caterpillars and retain these toxins into adulthood. For example, the monarch butterfly is known for its toxicity, which it acquires from milkweed plants .
Fish:
- There are numerous poisonous fish species. For instance, species of puffer fish contain tetrodotoxin, a potent toxin that can be fatal if ingested. Other examples include the spotted trunkfish and certain moray eels.
Frogs:
- Many frogs are poisonous, such as the poison dart frogs. These frogs secrete toxins through their skin, which can be harmful or even lethal if ingested. Additionally, some frogs like Bruno’s casque-headed frog and Greening’s frog are also venomous, meaning they can inject toxins through spines on their heads .

Butterflies:
- Butterflies often acquire their toxicity from the plants they consume as caterpillars.
- Aposematism is a common defense mechanism where bright colors warn predators of their toxicity.
- Some non-toxic butterflies mimic the appearance of toxic species to avoid predation.
Fish:
- Poisonous fish contain toxins that are harmful when ingested. Examples include puffer fish and moray eels.
- Venomous fish deliver toxins through bites, stings, or spines. Examples include the reef stonefish and lionfish.
- Venomous fish are more numerous than venomous snakes and are found in various habitats, primarily tropical waters.
Frogs:
- Poisonous frogs secrete toxins through their skin as a defense mechanism. Poison dart frogs are a well-known example.
- Venomous frogs like Bruno’s casque-headed frog and Greening’s frog can inject toxins through spines on their heads.
- The venom of these frogs can cause severe pain and other symptoms in predators and humans.