This is an image of an electrocardiogram Which statement describes the condition of the heart at the point indicated in the electrocardiogram?
(The arrow is pointed at the left slant of the peak)
The muscles of the atria depolarize.
The muscles of the ventricles depolarize.
The muscles of the atria repolarize.
The muscles of the ventricles repolarize.

the muscle because i learned about that i loved learning about it  hope i helped

Explanation:

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:

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