Give a reason why very big ears could be a disadvantage for an elephant?

Iknow the answer to 13 is b and 14 is d. i just need to know why the correct answers are correct

Asolution contains 180 g of glucose (c6h12o6) and 162 g of water. what is the mole fraction of glucose?

The volume of helium in a blimp is 6.28 x 10^9 millimeters. the density of helium in the blimp is .1786 kilogram/meter^3. find the mass of the helium in the blimp.