Which step in cellular respiration happens first?

a. pyruvate processing
b. electron transport chain
c. glycolysis
d. krebs cycle

Glycolysis

Glycolysis - breakdown of glucose molecule to 2 pyruvates which will go into next step/cycle (citric acid cycle aka Krebs cycle). I believe it is glycolysis that is the first step in cellular respiration. Complete oxidation of glucose via respiration = four step process used to convert chem energy in glucose to ATP.

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)]