If the weight of liquid displaced and the weight of an object are the same, the object will float in the liquid.
From Archimedes principle, when an object is immersed in fluid, a force called upthrust supports it and it equal to the weight of the liquid displaced.
When in a liquid, the weight of the liquid displaced is the same as that of the of the object, it will float and not sink.
B.The unknown solution had the lower concentration.
Explanation:
Osmosis is a phenomenon in which the molecules of the solvent has a tendency to move through a membrane which is semipermeable from lower concentrated side to the higher concentration side, so that the concentrations on both sides of the membrane must be equal.
So the unknown solution may have lesser concentration than the isotonic solution so that molecules of that solution move from less concentrated side to the more concentrated side, so its level drops.
As the object falls, it moves faster and faster. Gravity is considered a universal force because it acts between any two masses anywhere in the universe. For example, there is a gravitational pull between the Sun and the Moon. Even small masses attract one another.