Hrough which plant structures is oxygen gas released into the air as a waste product of photosynthesis?

Stomata

Stomata are the plant structures through which oxygen gas is released into the air as a waste product of photosynthesis. Stomata are tiny pores in the epidermis of a plant through which gases (carbon dioxide and oxygen), and water vapor enter and exit. A stoma contains a cell wall, chloroplast, a vacuole and a cell nucleus.

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)]

bradykinin is a physiologically and pharmacologically active peptide of the kinin group of proteins, consisting of nine amino acids.