What type of bond forms between nitrogen and oxygen, and why?

A. The height of a plant increases in the absence and presence of the nutrients

B. When the amount of nutrients available to the plant decreases, its height increases.

C. The amount of nutrients available to a plant is independent of how tall the plant gets

D. When the amount of nutrients available to the plant increases, its height also increases.

Because this is a positive correlation, if the nutrient concentration increases or decreases, plant height will either increase or decrease accordingly.

While analyzing data, scientists tend to observe cause-and-effect relationships. These relationships can be quantified using correlations. Correlations measure the amount of linear association between two variables. There are three types of correlations:

Positive correlation: 
As one variable increases, the other variable also increases. This is also known as a direct correlation.

Negative correlation: 
As one variable increases, the other decreases. The opposite is true if one variable decreases. A negative correlation is also known as an inverse correlation or an indirect correlation.

No correlation: 
There is no connection or relationship between two variables.

A. embryo

B. fetus

C. infant

D. zygote

Human intercourse consists of the male introducing sperm into the female’s reproductive system. Sperm may then pass through the female’s reproductive system to the Fallopian tubes where one sperm fertilizes an ovum, creating a zygote. The zygote passes out of the Fallopian tube and implants into the uterine wall to begin gestation. Over nine months, the zygote develops and grows into an embryo and then a fetus. An infant is the baby that is born.

A. As a result, Mendel developed several theories that have since been disproved.

B. Mendel realized he was on an incorrect track, which led him to other experimental media

C. As a result, Mendel developed foundational conclusions that are still valued and followed today.

D. Mendel collaborated with others interested in genetics to develop heredity guidelines we still use today

Mendel developed theories of genetics that scientists around the world use today.

From experiments with garden peas, Mendel developed a simple set of rules that accurately predicted patterns of heredity. He discovered that plants either self-pollinate or cross-pollinate, when the pollen from one plant fertilizes the pistil of another plant. He also discovered that traits are either dominant or recessive. Dominant traits are expressed, and recessive traits are hidden.

Mendel’s Theory of Heredity

To explain his results, Mendel proposed a theory that has become the foundation of the science of genetics. The theory has five elements:

• Parents do not transmit traits directly to their offspring. Rather, they pass on units of information called genes.
• For each trait, an individual has two factors: one from each parent. If the two factors have the same information, the individual is homozygous for that trait. If the two factors are different, the individual is heterozygous for that trait. Each copy of a factor, or gene, is called an allele.
• The alleles determine the physical appearance, or phenotype. The set of alleles an individual has is its genotype.
• An individual receives one allele from each parent.
• The presence of an allele does not guarantee that the trait will be expressed.

A. Aniline

B. Pyridine

C. Pure water

D. Sodium hydroxide

A pH of 7 is a neutral solution, which is how pure water is classified. Researchers can determine the strength of an acid or a base by measuring the pH of a solution. The pH value describes how acidic or basic a solution is. On pH scale, shown below, if the number is less than 7 the solution is acidic. A pH greater than 7 means the solution is basic. When the pH is exactly 7, the solution is neutral.

A. Condensation

B. Deposition

C. Evaporation

D. Melting

Unlike condensation, deposition, and melting, evaporation is dependent not only on the temperature, but also on the amount of a substance available.

Condensation is the change of a gas or vapor to a liquid. A change in the pressure and the temperature of a substance causes this change. The condensation point is the same as the boiling point of a substance. It is most noticeable when there is a large temperature difference between an object and the atmosphere. Condensation is also the opposite of evaporation.

Evaporation is the change of a liquid to a gas on the surface of a substance. This is not to be confused with boiling, which is a phase transition of an entire substance from a liquid to a gas. The evaporation point is the same as the freezing point of a substance. As the temperature increases, the rate of evaporation also increases. Evaporation depends not only on the temperature, but also on the amount of substance available.

Freezing is the change of a liquid to a solid. It occurs when the temperature drops below the freezing point. The amount of heat that has been removed from the substance allows the particles of the substance to draw closer together, and the material changes from a liquid to a solid. It is the opposite of melting.

Melting is the change of a solid into a liquid. For melting to occur, enough heat must be added to the substance. When this is done, the molecules move around more, and the particles are unable to hold together as tightly as they can in a solid. They break apart, and the solid becomes a liquid.

Sublimation is a solid changing into a gas. As a material sublimates, it does not pass through the liquid state. An example of sublimation is carbon dioxide, a gas, changing into dry ice, a solid. It is the reverse of deposition.

Deposition is a gas changing into a solid without going through the liquid phase. It is an uncommon phase change. An example is when it is extremely cold outside and the cold air comes in contact with a window. Ice will form on the window without going through the liquid state.