Answer:
A polar molecule simply means the charges are uneven throughout the molecule. Some parts are slightly negative (outside the oxygen), and some parts are slightly positive (outside the hydrogen atoms). A covalent bond happens when atoms share their electrons with each other. So, polar covalent just means that the atoms aren't sharing their electrons evenly, creating slight charges in the molecule. Water is polar covalent because the highly electronegative oxygen atom pulls electrons to it, making the region around the oxygen more negative than the areas around the two hydrogen atoms.
1. Sensory Receptors: Detects changes of internal or external stimulus.2. Integrating center: sends signals to proper areas of the body regarding the stimulus.3. Effectors: Respond to stimulus to maintain homeostasis.
Oxygen us the most common element
