Why do astronomers think that there may be other advanced civilizations?

What technologies are astronomers using to look for life on other planets? Why?

What are the challenges of looking for Dyson spheres?

Astronomers have theorized that there could be three types of civilizations. What are they? How would they be recognized? Which one has been ruled out so far?

Do you think an advanced civilization may exist in the universe? Why or why not?

PLZ help :)

Monarch butterflies have brightly colored orange wings with black patterns on them, making them easily visible to birds that eat butterflies and moths, yet birds rarely eat the monarchs. likewise, the monarch caterpillars are brightly striped yellow and white and black, and they also are rarely eaten by birds, although some wasps will attack them and feed them to their young. what can be inferred from these observations? monarchs must threaten and attack birds, but not wasps. monarchs have a way of discouraging bird predation that does not involve hiding. monarchs’ wings are so colorful that most birds must find them difficult to eat. monarchs lay more eggs than other less conspicuous butterflies.