Answer the following question given this paragraph: The crystal structure of ionic compounds is strong and rigid. It takes a lot of energy to break all those ionic bonds. As a result, ionic compounds are solids with high melting and boiling points. You can see the melting and boiling points of several different ionic compounds in the Table below . To appreciate how high they are, consider that the melting and boiling points of water, which is not an ionic compound, are 0C and 100C, respectively. Q: In celsius, what is the boiling point of water? Choices: - zero degrees - two hundred twelve degrees - ninety eight degrees - one hundred degrees A:
one hundred degrees
(Question)
Answer the following question given this paragraph: Did you ever hear an echo of your own voice? An echo occurs when sound waves bounce back from a surface that they can't pass through. The woman pictured here is trying to create an echo by shouting toward a large building. When the sound waves strike the wall of the building, most of them bounce back toward the woman, and she hears an echo of her voice. An echo is just one example of how waves interact with matter. Q: What is heard when sound waves bounce back from a surface that they can't pass through? Choices: - radio - ultrasound - loop - echo A:
(Answer)
echo
Ques: Answer the following question given this paragraph: Rolling friction is friction that acts on objects when they are rolling over a surface. Rolling friction is much weaker than sliding friction or static friction. This explains why most forms of ground transportation use wheels, including bicycles, cars, 4-wheelers, roller skates, scooters, and skateboards. Ball bearings are another use of rolling friction. You can see what they look like in the Figure below . They let parts of a wheel or other machine roll rather than slide over on another. Q: What is friction that acts on objects while it is rolling over a surface called? Choices: - blowing friction - opposing friction - surface friction - rolling friction A:
Ans: rolling friction
(Q).
Answer the following question given this paragraph: Topsoil has the highest proportion of organic material. Topsoil is essential for farming. Q: What layer of soil, essential for farming, has the highest proportion of organic material? Choices: - bedrock - humus - subsoil - topsoil A:
(A).
topsoil
Ques:Answer the following question given this paragraph: Some traits are controlled by more than one gene. They are called polygenic traits. Each gene for a polygenic trait may have two or more alleles. The genes may be on the same or different chromosomes. Polygenic traits may have many possible phenotypes. Skin color and adult height are examples of polygenic traits in humans. Think about all the variation in the heights of adults you know. Normal adults may range from less than 5 feet tall to more than 7 feet tall. There are people at every gradation of height in between these extremes. Q: Polygenic traits are controlled by more than one of these? Choices: - phenotypes - chromosomes - genomes - genes A:

Ans:genes
Answer the following question given this paragraph: Covalent bonds form because they give atoms a more stable arrangement of electrons. Look at the hydrogen atoms in Figure above . Alone, each hydrogen atom has just one electron. By sharing electrons with another hydrogen atom, it has two electrons: its own and the one in the other hydrogen atom. The shared electrons are attracted to both hydrogen nuclei. This force of attraction holds the two atoms together as a molecule of hydrogen. Q: What bonds form because they give atoms a more stable arrangement of electrons? Choices: - Hydrogen bond - Ionic bond - Polar bond - covalent A:
covalent