Why do the walls of the trachea not collapse when there is less air in it ?

With the word calcite wich completes the analogy mineral, erosion, marble, or aragonite

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.

In a village where the proportion of individuals who are susceptible to malaria is .70 and population is at hardy-weinberg equilibrium what population is heterozygous hba/hbs