Problem: The properties of matter depend on the types of atoms that matter is made of. Matter can exist in two forms. It can be a pure substance. This means it is not mixed with anything. It can also be a combination of different substances. This means it can be a mix of different types of atoms. You may recall that atoms differ based on the numbers of protons they contain. Some atoms contain only one proton such as Hydrogen. Other atoms contain many protons. There are many types of atoms. For example, Helium has two protons. An Oxygen atom has eight. Water is composed of a two types of atoms. Water is made of two Hydrogen atoms and one Oxygen atoms. There are only so many types of atoms. These atoms can be mixed into an almost limitless amount of substances. So what do we call a substance that has only a single type of atom?

Question: "What two forms of matter are there?"

Answer: "It can be a mix of different types of atoms"
Answer: no

Problem: She led the way into the cheerful schoolroom, where big girls and little girls were sitting about, amusing themselves in the quiet of a long Sunday afternoon. Several of the younger children ran to her as she came in, and stood holding fast to the folds of her black habit, staring up at the strangers, while she explained the kind of instruction given, the system, and the order reigning in each department. Finally, she persuaded a little girl, only six years old, to take her dusky face out of the long flowing veil of the nun, and show how quickly she could read a sentence that Sister Winifred wrote on the blackboard. Then others were called on, and gave examples of their accomplishments in easy arithmetic and spelling. The children must have been very much bored with themselves that stormy Sunday, for they entered into the examination with a quite unnatural zest. Two of the elder girls recited, and some specimens of penmanship and composition were shown. The delicate complexion of the little nun flushed to a pretty wild-rose pink as these pupils of hers won the Colonel's old fashioned compliments.

Question: "Are these students equal in age?"

Answer: "No"
Answer: yes

Problem: Water flowing over Earths surface or underground causes erosion and deposition. Water flowing over a steeper slope moves faster and causes more erosion. How water transports particles depends on their size. When water slows down, it starts depositing sediment. This process starts with the largest particles first. Runoff erodes the land after a heavy rain. It picks up sediment. Runoff carries most of the sediment to bodies of water. Mountain streams erode narrow, V-shaped valleys and waterfalls. Erosion and deposition by slow-flowing rivers create broad floodplains and meanders. Deposition by streams and rivers may form alluvial fans and deltas. Floodwaters may deposit natural levees. Erosion and deposition by groundwater can form caves and sinkholes. Stalactites and stalagmites are mineral deposits. They build up in caves as water continues to drip.

Question: "What kind of deposits build up in caves as water continues to drip?"

Answer: "Erosion"
Answer:
no