Which of the following statements is true? a. only a few animal and plant cells have vacuoles. b. all animal cells have at least one vacuole, but only some plant cells have vacuoles. c. all plant cells have at least one vacuole, but only some animal cells have vacuoles. d. all animal and plant cells have at least one vacuole.

answer; i believe that the correct answer is ; males are hemizygous for the x chromosome;

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: