Potential difference across resting membrane is negatively charged. This is due to differential distribution of the following ions.

1. Na⁺ and K⁺ ions

2. CO₃^2- and Cl^- ions

3. Ca²⁺ and Mg²⁺ ions

4. Ca⁺⁴ and Cl^- ions

Resting membrane potential is maintained by

1. hormones

2. neurotransmitters

3. ion pumps

4. None of these