What makes the great pyramid unusual among the places on antipater’s list?

Answer : It is only one of those ancient sights which still exist and gives ancient antiquity to the great pyramid in Egypt. It is believed that the pyramids are the definition of prayers that still remains in the heart of the local people.

It is also one of seven wonders of the world that is under world heritage. Pyramids where only found in Egypt and nowhere else.

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.

ca has a crystalline lattice with positive ions (since it is a metal, metals are positively charged) and electrons flow freely in its structure since the ca atoms have a large nuclear radius so the electrons are not tightly held, therefore the electrons can flow freely since they are not being highly attracted by the nucleus. moreover, one of the properties of metals are that they are conductors of electricity, thus proving ca is the element.