Answer:
Mammals first appeared
Explanation:
The dinosaurs became extinct one million years after the Cenozoic era started. The mammals first appeared as the modern culture first appeared in that era.
Meiosis is important because it ensures that all organisms produced via sexual reproduction contain the correct number of chromosomes.
Athletics would be the easiest choice here
Sports are an active that takes up a lot of different organ systems. When running I use my muscular system and cardiovascular system the most. The cardiovascular system directly controls running because it helps prevent me from getting tired and worn out faster.
Hope this helps :)
