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

A person can be a universal blood donor or acceptor. A universal blood donor has type O blood, while a universal blood acceptor has type AB blood.

There are several different types or groups of blood, andthe major groups are A, B, AB, and O. Blood group is a way to classify blood according to inherited differences of red blood cellantigensfound on the surface of a red blood cell. The type ofantibodyin blood also identifies a particular blood group. Antibodies are proteins found in the plasma. They function as part of the body’s natural defense to recognize foreign substances and alert the immune system.

Depending on which antigen is inherited, parental offspring will have one of the four major blood groups. Collectively, the following major blood groups comprise the ABO system:

• Blood group A: Displays type A antigens on the surface of a red blood cell and contains B antibodies in the plasma.
• Blood group B: Displays type B antigens on the red blood cell’s surface and contains A antibodies in the plasma.
• Blood group O: Does not display A or B antigens on the surface of a red blood cell. Both A and B antibodies are in the plasma.
• Blood group AB: Displays type A and B antigens on the red blood cell’s surface, but neither A nor B antibodies are in the plasma

In addition to antigens, the Rh factor protein may exist on a red blood cell’s surface. Because this protein can be either present (+) or absent (-), it increases the number of major blood groups from four to eight: A+, A-, B+, B-, O+, O-, AB+, and AB-.

If the cohesion between particles decreases, then the particles must be undergoing a phase change that allows particles to move farther apart. This happens when a substance vaporizes and turns from liquid to gas. Any phase change that moves to the right in the diagram above requires energy to be added to the system because the substance has more energy at the end of the phase change. The phase changes aremelting,vaporization (boiling), andsublimation. When energy is added, particles move faster and can break away from each other more easily as they move to a state of matter with a higher amount of energy. This is most commonly done by heating the substance.

Robert Hooke discovered the first cells in the mid-eighteenth century. The cell theory is a theory because it is supported by a significant number of experimental findings. The cell theory took many years to be developed because microscopes were not powerful enough to make such observations.

This theory, or in-depth explanation, about cells consists of three parts:

• All living things are composed of one or more cells.
• Cells are alive and represent the basic unit of life.
• All cells are produced from pre-existing cells.

In solids, particles are usually closer together than in other states of matter because of the strong cohesive forces between the particles.

• Solids, liquids, gases, and plasmas differ from one another in the amount of energy that the particles have and the strength of the cohesive forces that hold the particles together.
• Cohesion is the tendency of particles of the same kind to stick to each other.
• A solid has the lowest amount of energy because its particles are packed close together. Liquids have more energy than a solid, and gases have more energy than solids or liquids because the cohesive forces are very weak.

Atissueis a group of cells with similar structure and function and similar extracellular substances located between the cells. The table below describes the four primary tissues found in the human body.

body.

In this reaction, two elements are trading places hence double-replacement. In the reactants, zinc and bromide ions are together, and potassium and hydroxide ions are together. In the products, zinc and hydroxide ions are together, and potassium and bromide ions are together.

Both litmus paper and a pH scale can be used to indicate whether a solution is acidic. However, a pH scale can also determine the strength of an acid.

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.

The number of protons, 28, gives the atomic number, which identifies this atom as nickel. The mass is the number after the dash in the isotope name, which is determined by adding the numbers of protons and neutrons (28 + 32 = 60).

Homeostasisis the existence and maintenance of a relatively constant environment within the body. Each cell of the body is surrounded by a small amount of fluid, and the normal functions of each cell depend on the maintenance of its fluid environment within a narrow range of conditions, including temperature, volume, and chemical content. These conditions are known asvariables. For example, body temperature is a variable that can increase in a hot environment or decrease in a cold environment.

There are two types of feedback mechanisms in the human body: negative and positive.

• Negative Feedback: Most systems of the body are regulated by negative feedback mechanisms, which maintain homeostasis. Negative means that any deviation from the set point is made smaller or is resisted. The maintenance of normal blood pressure is a negative-feedback mechanism. Normal blood pressure is important because it is responsible for moving blood from the heart to tissues.
• Positive Feedback: Positive-feedback mechanisms are not homeostatic and are rare in healthy individuals. Positive means that when a deviation from a normal value occurs, the response of the system is to make the deviation even greater. Positive feedback therefore usually creates a cycle leading away from homeostasis and, in some cases, results in death. Inadequate delivery of blood to cardiac muscle is an example of positive feedback.