Final answer:
Calderas can form lakes after filling with water post-collapse and may also host new volcanic cones or domes due to ongoing volcanic activity beneath the surface.
Step-by-step explanation:
Within a caldera, two significant features that may form are lakes and new volcanic cones or domes. Calderas are large depressions that occur when a volcano collapses into itself after an eruption. An example is Crater Lake in Oregon, which formed about 7,000 years ago after the explosion and collapse of Mount Mazama. Over time, the caldera can fill with water, creating a lake. Additionally, subsequent volcanic activity may lead to the formation of new volcanic structures such as cones or domes within the caldera, as magma finds new paths to the surface.
Another interesting aspect can occur on bodies like Io, Jupiter's moon, where calderas can erupt with lava fountains and create colorful deposits of sulfur and sulfur dioxide around the vents. Similarly, on Earth, calderas can result from hot mantle material rising due to tectonic plates moving over stationary hotspots, as observed with the Yellowstone hotspot.