Answer - A substance is matter that has a uniform and definite composition. All samples of substances, sometimes called pure substances, have identical properties.
There are 7 valence electrons in the atom :)
Cruising at 35,000 feet in an airliner, straight toward the east,
at 500 miles per hour.
Since your speed is not changing and you're moving in a straight line,
your acceleration is zero.
B is true because liquids are still more compact than gases, although they are loose, they aren't completely free. They also don't have a definite volume, making them assume the shape of their container. As for compression, liquids are harder to compress compared to gases.