Usually is only because of blood vessels breaking in the skin.
The answer is letter A. In most organisms cellular respiration usually involves oxygen to produce the most energy. Except in the process of fermentation, where the cells are deprived with oxygen causing it to form bacteria and other forms of organisms within the fermented sample.
The pectoral girdle articulates with the axial skeleton only at the Sternoclavicular ligament<span>. The pectoral girdle connects the upper limbs to the axial skeleton and serves as the attachment site for the muscles of the upper back, chest and neck. The clavicle is the only long bone that lies in a horizontal position in the body. it has three regions; the medial end, the lateral end, and the shaft. The medial end has a triangular shape and articulates with the manubrium portion of the sternum. This forms sternoclavicular joint, which is the only bony articulation between the pectoral girdle of the upper limb and the axial skeleton. </span>
