Question

the asteroid that hit earth about 66 million years ago caused what major event?
the start of the ice age
the formation of the grand canyon
the extinction of the dinosaurs
the first appearance of life

Explanation:

The asteroid impact around 66 million years ago is widely associated with the Cretaceous - Paleogene (K - Pg) extinction event. This event led to the extinction of non - avian dinosaurs. The Ice Age started much later (around 2.6 million years ago). The Grand Canyon's formation is due to geological processes like erosion over a long period (not an asteroid impact). The first appearance of life was billions of years ago (around 3.5 - 4 billion years ago).

Answer:

The extinction of the dinosaurs