Which type of scientific investigation could involve hypothesizing which density of liquid refracts more light than water?

The excretory system,need answers for all: )

The number at the end of an isotope’s name is the number.

What rule is used to determine how many covalent bonds an element can form? a. the number of covalent bonds is equal to six c the number of covalent bonds is equal to five minus the group number plus the group number b. the number of covalent bonds is equal to eight d. none of the above minus the group number select the best answer from the choices provided