What conditions allowed so many different kinds of mammals to evolve during the Cenozoic Era?

A. Grasses evolved providing food to larger grazing animals, no dinosaurs which made way for mammals
B. Overpopulation of ocean algae allowed for more fish to thrive following more species of fish to exist
C. No dinosaurs so mammals were forced to evolve or die
D. More macrobiotic organisms caused the evolution process to happen at a quicker rate

Which way do the nitrogenous bases in dna pair up? a. a and g; t and c b. a and c; t and g c. a and t; g and c d. a and a; t and t; g and g; c and c

Plz ! ive been stuck on this forever

Even though the ostrich is a flightless bird, ostriches still possess wings that stretch approximately two meters across when fully extended. scientists speculate that when dinosaurs became extinct, some of the birds that lived during that time became land dwellers since they were able to consume the food that the dinosaurs once ate. over time, these species grew larger and heavier. eventually, the ostrich species became too big to fly. the wings found on ostriches are known as a. analogous structures. b. homologous structures. c. vestigial structures. d. symmetrical structures.