Muscle cells constantly need to remove sodium ions, na+, out of the cell and transport potassium ions, k+, into the cell in order to maintain homeostasis and for the muscles to work properly. both ions are moved against their concentration gradient. which of the following scenarios is depicting the sodium (na+)-potassium(k+) pump? a because polar molecules can pass through the bilipid layer. d because molecules cannot cross through the bilipid layer. d because a protein is needed for nonpolar molecules to cross the membrane. d because the molecules move from a low concentration to a high concentration.

The right answer is D because the molecules move from a low concentration to a high concentration.

The sodium-potassium pump is responsible for maintaining hydric balance in the body, the contraction of striated and smooth muscles, the maintenance of blood pressure and the transmission of nerve impulses in neurons. For this purpose, this protein transports sodium ions outside a cell and introduces potassium ions, using the energy of ATP degradation. The cell is then depolarized. The protein is particularly active during physical exertion.

the darker peppered moth species were favored due to the fact that the industrial revolution had made all the nearby trees a darker color instead of white.

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)]