Correct option is B
Trilobites are among the most significant and characteristic fossils of the Cambrian era. They were marine arthropods that lived from the Early Cambrian to the end of the Permian period. The Spiti Valley, which is renowned for its rich fossil deposits, contains abundant trilobite fossils from the Cambrian period. Trilobites are crucial in understanding early marine ecosystems, biodiversity, and the evolutionary history of arthropods.
Information Booster:
Trilobites are often used as index fossils because they help in dating and correlating the age of sedimentary rocks, especially from the Cambrian period. They exhibit a variety of shapes, sizes, and structures, with their exoskeletons preserved as fossils. The Spiti Valley's Cambrian deposits reveal a diverse range of trilobite species, giving us insight into the early development of marine life.
Additional Information:
- Ammonites: These fossils are characteristic of the Mesozoic era, especially the Jurassic and Cretaceous periods, and are not found in Cambrian deposits. They are extinct marine mollusks related to modern cephalopods.
- Mosquitoes: Mosquitoes are relatively recent insects that appeared long after the Cambrian period. Fossils of mosquitoes are typically found in Cenozoic era deposits.
- Glossopteris: This is a type of seed fern that lived during the Permian period and is associated with the Gondwana landmass, not the Cambrian era. It is found primarily in the Permian deposits of the Southern Hemisphere, not in Cambrian rocks.
