The end of the Snowball Earth era is associated with the start of which major diversification event?

• A. Development of land plants
• B. Cambrian explosion
• C. Silurian forests
• D. Paleozoic glaciation

Answer: (B)

The question tests how dramatic climate shifts can open ecological opportunities for life. When Snowball Earth ended, deglaciation warmed oceans, increased nutrient input, and higher oxygen levels. That ecological release allowed many organisms to experiment with new body plans and occupy diverse ecological niches, leading to a rapid burst of evolution known as the Cambrian explosion. This event marks the sudden appearance of many major animal groups and hard-bodied organisms in the fossil record, aligning with the post-glacial recovery.

The other options don’t fit this timing or nature. Land plants colonized land later, in the Paleozoic era; the Silurian forests came after that, and Paleozoic glaciation refers to climate events rather than a diversification episode.