Answer:
4
Explanation:
Carbon has four valence electrons, so it can achieve a full outer energy level by forming four covalent bonds. When it bonds only with hydrogen, it forms compounds called hydrocarbons. Carbon can form single, double, or triple covalent bonds with other carbon atoms.
6CO2 + 6H20 + (energy) → C6H12O6 + 6O2
Carbon dioxide + water + energy from light produces glucose and oxygen.
Pectinate muscles are parallel ridges in the walls of the atria of the heart. The name is due to their resemblance to the teeth of a comb (pecten). The heart is the organ pumps blood to all parts of the body. It is made up of four chambers, that is, right and left ventricles, left and right atria, and the blood vessels, Pulmonary artery, pulmonary vein, aorta, and venacava. An auricles are pouch like structure that increase the total filling capacity of the atrium and also increase the volume of blood that an atrium is able to contain.
Cell has cell membrane<span> (also known as the </span>plasma membrane<span> or </span>cytoplasmic membrane<span>) it is a </span>biological membrane<span> that separates the </span>interior<span> of all </span>cells<span> from the </span>outside environment.<span> The cell membrane is </span>selectively permeable<span> to </span>ions<span> and </span>organic molecules<span>and </span>controls the movement of substances<span> in and out of cells.</span><span>The basic function of the cell membrane is to protect the cell from its surroundings.</span>
