Which shows three human body parts in order from the simplest level of organization to the most complex? red blood cell → nervous system → bone tissue nervous system → bone tissue → red blood cell red blood cell → heart tissue → circulatory system bone tissue → red blood cell → nervous system

red blood cell → heart tissue → circulatory system

red blood cell → heart tissue → circulatory system

Explanation:

red blood cell → heart tissue → circulatory system shows three human body parts in order from the simplest level of organization to the most complex.

The biological levels of organization of living organisms from the simplest to the most complex are organelle, cells, tissues, organs, organ systems, organisms, populations, communities, ecosystem, and biosphere. The biosphere is the highest level of organization and it includes all of the other levels. Cells (such as red blood cells) are the basic structural and functional units of living organisms which combine together to form tissues (such as heart tissue). Collections of tissues also make organs (such as heart). An organ system (such as circulatory system) is also composed of functionally related organs.

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: