Which of the following is an example of the skeletal system interacting directly with the
respiratory system?

a the ribcage expands to allow air to enter the lungs.
b the muscles attached to bones contract to lift your leg.
c the marrow inside bones produces white blood cells.
d the vertebrae protect the spinal cord from injury,

What was darwins theory of common decent

Imagine a self-reactive t cell that has not undergone clonal deletion in the thymus (that is to say, it has escaped central tolerance). if it encounters self antigen in the absence of an infection or inflammation, what will happen to this self-reactive t cell? (select two answers) (a) the t cell undergoes clonal expansion. (b) the t cell gains effector functions. (c) the t cell undergoes apoptosis. (d) the t cell becomes activated. (e) the t cell becomes anergic.

Kudzu vines grow by climbing and wrapping around trees. trees covered by kudzu can die because they are starved of sunlight. what type of relationship exists between the trees and the kudzu growing on them?