Eons are the broadest category of geologic time, and we live in the phanerozoic eon. the phanerozoic eon is further divided into eras. what divides the three eras of the phanerozoic eon?
a. mass extinction events separate the three eras from each other.
b. the first life on earth and the first multicellular life on earth separate the three eras from each other.
c. the development of insects and the development of flying insects separate the three eras from each other.
d. the appearance of carbon on earth and the appearance of atmospheric oxygen separate the three eras from each other.

the two answers are a, the population of birds with large beaks will increase on the island, and c, the trait for large beaks will be passed on to future generations through natural selection. the reason for that is because if the birds that have beaks developed for eating small seeds lose all of their food, they will go hungry and eventually starve because they physically cannot eat the large seeds, therefore making the population of large beaked birds higher. also, if the trait of large beaks are dominant on the island over small beaks, then over time the large beaked birds will reproduce more and more, while the smaller beaked birds will reproduce less and less because they can't survive with the food provided. that leads to the trait of small beaks disappearing and the trait of large beaks taking over the island.

all these collisions do one thing, and that thing is explained in the last option. when dusst, rocks and ice collide, they harden and form giant layers of rocks or hard ice.

d)   to harden materials to form different parts of earth’s layers

hope it ,

bioteacher101

answer: i feel like it would be 3

explanation: