By cross-breeding a tiger and a lion, a hybrid animal was created, but was infertile. which evolutionary barrier caused the infertile offspring?

Astudent sees several ants walking up a wall following the exact same trail that an ant took earlier. she wants to apply the scientific method to determine how the ants detected the trail. which of these steps would come first in her application of the scientific method? perform an experiment by cleaning the scent away from part of the trail. draw a conclusion that the ants follow a scent trail. make a prediction about what the ants will do after she cleans away part of the trail. hypothesize that the ants are following a scent trail that the first ant left.

All of these things can block a bronchus and cause collapse of a lung except

Why may some young adults go through a quarter-life crisis? a. they are entering middle age and feel distressed about growing old. b. they feel insecure about themselves and their future. c. they have been promoted to more secure, better-paying jobs. d. they have developed more stable personal relationships.