**Answer:**

4.5 times 10 Superscript negative 3

**Explanation:**

In scientific notation, the decimal is always after the first number so 14.5 times 10 Superscript 2 and 0.78 times 10 Superscript negative 6 is eliminated.

In scientific notation.=, the subscript is always 10 so 5.7 times 4 Superscript 8 is eliminated which leaves you with4.5 times 10 Superscript negative 3.

**Answer:**

Porosity

**Explanation:**

Something that is permeable allows liquid or air to pass through it

Non Porous means doesn't allow liquid or air to pass through it, porosity is the opposite of this and allows liquid or air to pass through it.