Which long-term environmental change could allow some organisms to flourish?

drought
ice age
tsunami
large asteroid impact

What are chlorofluorocarbons made of

Flock x flock y flock z total pieces of food eaten (from previous page) 147 93 60 food percentage* % % % simulated number of birds in flock for 3rd generation** * divide each flock's total pieces of food by 300, the total number of pieces of food eaten. ** multiply the food percentage for each flock by the total number of birds (30).

What must be true for natural selection to heppen