One of the main reasons why mammals may have been able to evolve so quickly during the present era is due to the extinction of the main predators in the previous era. true or false

False, I'd say. Mammals usually adapt based on environment. Now, I know predators are "apart" of the environment, but I don't think that'd be it. I'd bet more money on saying mammals evolve based on environment adaptation. Sorry if I didn't answer your question or if I didn't get my point across well.

well, you see. the answer to your question is quite simple. the thing that is big, powerful, and over 9,000 is your mom.

if the type of the food available changes, then the frequency of beak types will change, because birds with beaks more suited to the available food will be more successful over time.