Resting membrane potential is the electrical potential energy produced by oppositely charged ions found on opposite sides of the plasma membrane when the cell is at rest.

A. Formed elements: Formed elements include red blood cells, white blood cells, and platelets, which together make up the cellular portion of blood. These are suspended within plasma but are not considered part of plasma itself.

B. Salts: Salts such as sodium, potassium, and chloride are present in plasma as electrolytes. While they are vital for maintaining osmotic balance and nerve conduction, they make up only a small fraction of plasma’s total volume.

C. Sugars: Glucose and other sugars circulate in plasma to provide energy for cells, but their concentration is relatively low. They are important solutes but do not represent the bulk of plasma.

D. Water: Plasma is composed of about 90–92% water, making it the main component. Water serves as the solvent that carries nutrients, hormones, gases, and waste products, enabling transport and regulation within the circulatory system.

A. 10: If atom X has 17 protons, it is chlorine. Its total electrons in the neutral state are also 17. Having 10 electrons in the valence shell would be impossible, since the outermost shell of chlorine can hold only up to 8 electrons.

B. 3: Three valence electrons are characteristic of elements in Group 13, such as aluminum. Chlorine belongs to Group 17, so it does not have three electrons in its outer shell.

C. 5: Five valence electrons correspond to elements in Group 15, such as nitrogen or phosphorus. Since chlorine is in Group 17, it cannot have five electrons in its valence shell.

D. 7: Chlorine has an electron configuration of 1s² 2s² 2p⁶ 3s² 3p⁵, which totals 7 electrons in its outermost shell. This matches its placement in Group 17, making 7 the correct number of valence electrons.