Your meaning is unclear. Dinosaurs certainly used plants as shelter and food. Plants would also be propagated by dinosaurs though this is instinctive and evolutionary.
if temperature drops quick enough, plants die. if plants die, the dinosaurs that eat plants die. if those dinosaurs die, then the carnivorous meat-eating dinosaurs die. then, all dinosaurs die.
Dinosaurs did not die out because of plants. They died out because of a lack of plants after an asteroid impact blocked out sunlight for months or years. With all the plants dead, the dinosaurs starved.
Jellyfish live side by side with plants in the ocean. They do not really do not interact with plants outside of eating some plants.
Plants evolved before dinosaurs, and dinosaurs depended on plants for food. The closest there came to "no plants" during the time of the dinosaurs was the mass extinction at the end, when plants died but left seeds behind that germinated when the dust thrown into the atmosphere by an asteroid impact settled and sunlight reached the surface. During that period of months or a few years without live plants, dinosaurs starved and died out.
yes most dinosaurs ate plants
Dinosaurs survived by eating other dinosaurs or plants.
They ate plants, fruits and other dinosaurs.
DINOSAURS!
Because there wasn't much else to eat. Additionally most plants looked appealing to dinosaurs.
2
Mammals and dinosaurs emerged in the Mesozoic era. Plants appeared in the Paleozoic era, which came before it.
Carnivores. The ones who eat plants are called herbivores.