Answer:
Cardiac muscle tissue
Explanation:
Myocardium or heart muscle is a special type of muscle (differ than striated and smooth) and it is the main tissue of the walls of the heart.
Heart muscle consists of individual heart muscle cells (cardiomyocytes) which are joined together by intercalated discs. It also contains collagen fibres and other substances that form the extracellular matrix.
Heart muscle has a "special" mode of contraction: action potential triggers the release of calcium ions from the cell's internal store, the sarcoplasmic reticulum.
The iris focuses light rays before they enter the posterior portion of the eye
Answer:
Argon
Explanation:
The element that has a complete valence electron shell is argon (Ar) since it is a noble gas in the last group on the periodic table. destinymitchell966
