Epithelial tissue covers the entire surface of many organisms. which term describes the structure directly below tissues in the hierarchical organization of life?
a) atoms
b) cells
c) molecules
d) organs

ionic bonds are two oppositely charged ions that attract. a sodium ion has a 1 positive charge; a chloride ion has a 1 negative charge. sodium and chloride have oppostive charged ions that attract which forms an ionic bond. a chemical bond formed when two atoms share electrons is called