3 - phosphate group (head) ; hydrophilic ; water and/ or polar substances
4 - is attracted to water and other polar substances.
Explanation:
Phospholipids have two parts: a hydrophilic head (phosphate group) and hydrophobic tails (fatty acids). Hydrophilic basically means a substance that is attracted to water (Hence, <em>hydro</em> - water and <em>phile</em> - loving), and thus, by virtue, to other polar substances (since water is polar).
