Question

Which one of the following organisms became extinct during the Cretaceous- Tertiary mass extinction event?

• A. Trilobite
• B. Ammonite
• C. Brachiopod
• D. Echinoderm

Answer 1

The Correct Option is B

The question asks which organism became extinct during the Cretaceous-Tertiary mass extinction event. To answer this question, let's look at the context and details of the extinction event and each of the given options:

• Cretaceous-Tertiary (K-T) Mass Extinction: This event occurred approximately 66 million years ago and is famous for the extinction of the dinosaurs. It marked a significant change in the planet's biodiversity, with around 75% of species becoming extinct.
• Ammonite: Ammonites were marine mollusks with spiral shells. They were very diverse and abundant in the oceans but went extinct during the K-T event. This makes them the correct answer to the question.
• Trilobite: Trilobites were marine arthropods that actually became extinct much earlier, during the end-Permian extinction, about 252 million years ago.
• Brachiopod: While brachiopods experienced significant reductions in their population during various extinction events, they did not become entirely extinct. Some species survive to this day.
• Echinoderm: This group includes starfish and sea urchins, among others. Like brachiopods, they also suffered population losses, but many species survived and still exist today.

Based on this information, the organism that became extinct during the Cretaceous-Tertiary mass extinction event is the Ammonite.

In conclusion, the right answer is Ammonite, as they were wiped out during the K-T extinction event.