The answer to the question is true
Development of the ozone layer
>> sharks and trilobites abundant in oceans
>> plants and animals colonize land
>> dominance of reptiles >> dominance of mammals
The answer is b
But I need to make this answer longer so it will be AT LEAST 20 CHARACTERS LONG!!!!!,
Their white fur helps them blend in with the snow and ice. A polar bear<span> has a layer of fat under its skin which helps it stay warm. It also has a thick layer of fur. hope this helps!!</span>