Please help!! Biology! 1. Why is it possible for the surface of a pond to freeze even though the water underneath is fluid?

2. Sugar dissolves in water, but is not an ionic compound. What does this tell you about sugar?

3. Water is used in the cells to help transport in the chemicals necessary to survive. Since cell membranes need to be able to hold in and hold out water without dissolving, what do you suspect cell membranes are made from? Why do you think this?

4. Remember "The Wicked Witch of the West" from The Wizard of Oz? She melted when doused with water. What do you think her cell membranes were made of, and why?

5. Find out why hot water freezes more quickly than cold water, and explain it here.

6. Explain why heavy water is heaver than regular water.

Explanation:

1 In order for water to freeze, it must reach a temperature of 0°C . This occurs at the surface of a lake, which is why it freezes.

However, water, being a special molecule, expands when it freezes, rather than contracts, meaning that the ice on top of the lake is less dense than the water underneath it.

2 Sugar will readily dissolve in water but doesn't form cations and anions in solution. That is, there are no charge carriers formed. Substances that only partially ionize into ions when dissolved in water are called weak electrolytes.

3 It is made of millions of smaller molecules that create a flexible and porous container. Proteins and phospholipids make up most of the membrane structure. The phospholipids make the basic bag. The proteins are found around the holes and help move molecules in and out of the cell.

5 when the hot water cools, it loses mass to evaporation. With less mass, the liquid has to lose less heat to cool, and so it cools faster. With this explanation, the hot water freezes first, but only because there's less of it to freeze.

6. Heavy water is the same as ordinary water except that the two hydrogen atoms (H-1) of the water molecule are replaced by two deuterium atoms

(H-2).

In ordinary water, each hydrogen atom has just a single proton in its nucleus. In heavy water, each hydrogen atom is indeed heavier, with a neutron as well as a proton in its nucleus.

they had the law tat factories that produces smoke cannot be built near residential buildings.

building of proper sewage system was done to ensure that the waste is carried away from the humans so that they do not get diseases from it.

also they built water systems to provide water in those areas which are drought prone.