Trình bày thí nghiệm và giải thích cơ chế thành lập phản xạ có điều kiện.

as many times as you want

i believe the answer would be b. hope it : )

answer : haversian

[explanation: -(compact bone is organized as parallel columns, known as haversian systems, which run lengthwise down the axis of long bones. these columns are composed of lamellae, concentric rings of bone, surrounding a central channel, or haversian canal, that contains the nerves, blood vessels, and lymphatic system of the bone)]

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