When an asteroid hit the Earth 65 million years ago, it threw a huge amount of dust into the atmosphere. This dust cloud stayed in the sky, blocking out the Sun for at least 10 years. Why did most of the animals on the Earth go extinct at this time? A. The dust cloud prevented plants from making food

B. The asteroid started fires that burned the Earth

C. The Sun turned off

According to abundant geological evidence, an asteroid roughly 10 km (6 miles) across hit Earth about 65 million years ago. This impact made a huge explosion and a crater about 180 km (roughly 110 miles) across. Debris from the explosion was thrown into the atmosphere, severely altering the climate, and leading to the extinction of roughly 3/4 of species that existed at that time, including the dinosaurs. Many asteroids of this type are now known; their orbits pass through the inner solar system and cross Earth's orbit. Some of these could potentially hit Earth in the future. Most, but not all are smaller than the one that hit us 65 million years ago.

Gaps in the Fossil Record

Fossils found in soil layers of different ages show a record of slow, gradual changes in species, with simple organisms gradually being replaced by more complex organisms, apparently by evolutionary processes driven by natural selection. For example, 1000 million years (abbreviate My) ago, the oceans held only simple organisms like algae, while the land was relatively lifeless. Fish fossils appear in strata after about 500-600 My ago; dinosaurs and giant reptiles were on the land by 200 My ago. Mammals were not common until after 65 My ago, and humanlike creatures appeared only in the last 4 My.In the late 1970s, a team of geochemists headed by Luis Alvarez and his son Walter Alvarez, both with connections to the University of California at Berkeley, was studying chemical changes in soil layers corresponding to breaks in the fossil record. In the soil layer that separates the Mesozoic Era from the Cenozoic Era, dating 65 My ago, they found an excess of the element iridium, which is common in meteorites. Meteorites are believed to be fragments of asteroids. Therefore, the Alvarez team theorized that an asteroid had hit Earth at this time, and that the debris ejected from the explosion were spread in the soil layer.

Explanation:

so b

a is the answer to this question

explanation: