Ahormone attaches to a target cell at a receptor protein. what do you know about this hormone?
it is steroid hormone
it will bind directly to dna
it is able to pass through cell membranes
it will not enter the nucleus

answer: the blood-brain barrier is a layer of specialized membranes and cell processes designed to keep undesirable substances from passing from the bloodstream into the precious tissues of the brain. while the blood-brain barrier does keep most bad things out of the central nervous system, it is not impermeable.

explanation:

because they are eaten by the frog and the frog getseaten by the snake and the snake by the eagle