Compare the two theories regarding the evolution of dinosaurs and then consider the cladogram above. although the two theories differ on the evolutionary path of dinosaurs, they agree that
a) dinosaurs, reptiles, and birds had a common ancestor.
b) dinosaurs evolved much later than birds or reptiles.
c) the branch containing dinosaurs evolved before either reptiles or birds.
d) dinosaurs should be on the same main branch as snakes, lizards and crocodiles.

A) dinosaurs, reptiles, and birds had a common ancestor

Explanation:

The dinosaurs have not evolved as a separate phylum that has not close relations with other animals, but instead they share a common ancestor with the likes of the reptiles and the birds. The reptilians have actually emerged before the dinosaurs, but the dinosaurs managed to take up the top niches in the food chain after they appeared never the less. The birds on the other hand are actually an evolutionary product of the diversification of the dinosaurs. the birds have actually evolved from small bipedal dinosaurs, that over time started to take up new way of life and appearance in order to conquer the skies.

explanation:

b,bacteria convert nitrates

into nitrogen gas.

d,plants and animals take in

and use nitrogen compounds.

e,bacteria break down waste    

products and return nitrogen  

to the soil.

a,bacteria convert atmospheric

nitrogen to ammonia.

c,bacteria convert ammonia

to nitrites and nitrates.

blah

explanation:

bc blah