In which state of matter do the particles of iron have the lowest amount of cohesion?

The autonomic nervous systemis responsible for activities that arenonvoluntaryand under unconscious control. This system controls glands and the smooth muscles of internal organs, heart rate, breathing, and digestion. The autonomic nervous system is further divided into the following:

• Sympathetic nervous system: The sympathetic nervous system focuses on emergency situations by preparing the body forfight or flight. (Sympathetic = Stress)
• Parasympathetic nervous system: The parasympathetic nervous system controls involuntary processes unrelated to emergencies. This system deals with “rest or digest” activities. (Parasympathetic = Peace)

Thesomatic nervous systemprimarily controlsvoluntaryactivities such as walking and riding a bicycle. Thus, this system sends information to the CNS and motor nerve fibers that are attached to skeletal muscle.

Oral Cavityis the first part of the digestive system. It is bounded by the lips and cheeks and contains the teeth and tongue. Its primary function is to masticate, or chew, and moisten the food.

Pharynx, or throat, connects the mouth to the esophagus.

Esophagusis a muscular tube about 25 centimeters long. Food travels down it to the cardiac sphincter of the stomach.

Pyloric sphincter. The exit of the stomach.

Small intestineis about 6 meters long and consists of three parts: duodenum, jejunum, and ileum.

Large intestine, consists of the cecum, colon, rectum, and anal canal. The cecum is located where the small and large intestine meet. The primary function of the large intestine is to compress the waste and collect any excess water that can be recycled.

Colonis about 1.5 to 1.8 meters long and consists of four parts: the ascending, transverse, descending, and sigmoid colon.

Skeletal muscle: This muscle cell is striated, long, and cylindrical. There are many nuclei in a skeletal muscle cell. Attached to bones in the body, skeletal muscle contracts voluntarily, meaning that it is under conscious control.

Smooth muscle: This muscle consists of nonstriated muscle cells that are spindle-shaped. Like cardiac muscle cells, smooth muscle cells contain one nucleus. This muscle type is found in the walls of internal organs like the bladder and stomach. Smooth muscle contraction is involuntary and controlled by the autonomic nervous system.

Cardiac muscle: This muscle consists of muscle cells that are striated, short, and branched. These cells contain one nucleus, are branched, and are rectangular. Cardiac muscle contraction is an involuntary process, which is why it is under the control of the autonomic nervous system. This muscle is found in the walls of the heart.

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.

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.

A cell copies its DNA during the S phase, and nucleotides are the building blocks of DNA. Thus, the step preceding the S phase, theG1phase, is the phase of the cell cycle when the cell would contain the most nucleotides.

For a cell to divide into more cells, it must grow, copy its DNA, and produce new daughter cells. Thecell cycleregulates cellular division. This process can either prevent a cell from dividing or trigger it to start dividing.

The cell cycle is an organized process divided into two phases:interphaseand theM (mitotic) phase. During interphase, the cell grows and copies its DNA. After the cell reaches the M phase, division of the two new cells can occur. The G1, S, and G2phases make up interphase.

• G1:The first gap phase, during which the cell prepares to copy its DNA
• S:The synthesis phase, during which DNA is copied
• G2:The second gap phase, during which the cell prepares for cell division

It may appear that little is happening in the cell during the gap phases. Most of the activity occurs at the level of enzymes and macromolecules. The cell produces things like nucleotidesfor synthesizing new DNA strands, enzymes for copying the DNA, and tubulin proteins for building the mitotic spindle. During the S phase, the DNA in the cell doubles, but few other signs are obvious under the microscope. All the dramatic events that can be seen under a microscope occur during the M phase: the chromosomes move, and the cell splits into two new cells with identical nuclei.

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 eitherself-pollinateorcross-pollinate, when the pollen from one plant fertilizes the pistil of another plant. He also discovered that traits are eitherdominantorrecessive. 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 calledgenes.
• For each trait, an individual has two factors: one from each parent. If the two factors have the same information, the individual ishomozygousfor that trait. If the two factors are different, the individual isheterozygousfor that trait. Each copy of a factor, orgene, is called anallele.
• The alleles determine the physical appearance, orphenotype. The set of alleles an individual has is itsgenotype.
• An individual receives one allele from each parent.
• The presence of an allele does not guarantee that the trait will be expressed.

Because more solute could be added and dissolve, the solution has not yet reached its limit and is considered unsaturated. Because all the solute dissolves, the particles in the mixture are evenly distributed as a homogenous mixture.

• Amixtureis when elements and compounds are physically, but not chemically, combined.
• Ahomogeneousmixture is when substances mix evenly and it is impossible to see individual components. Aheterogeneousmixture is when the substances mix unevenly and it is possible to see individual components.
• Asolutionis a type of homogeneous mixture that is formed when a solute dissolves in a solvent.
• The concentration of a solution is the amount of a substance in a given amount of solution. Anunsaturatedsolution has the ability to dissolve more solute and asaturatedsolution has already reached the limit of solute it can dissolve.

Inductive reasoning involves making specific observations and using them to make broad statements. The student observes that all of the tigers have the same stripe pattern. He can use this observation to make the broad statement that all the tigers’ offspring will have the same stripe pattern.

Inductive reasoninginvolves drawing a general conclusion from specific observations. This form of reasoning is referred to as the “from the bottom up” approach. Information gathered from specific observations can be used to make a general conclusion about the topic under investigation. In other words, conclusions are based on observed patterns in data.

The cardiovascular system is closely associated with hematopoiesis because it includes the heart and blood vessels, which are responsible for circulating blood throughout the body. Hematopoiesis, the process of blood cell formation, primarily occurs in the bone marrow, which is part of the skeletal system. However, the cardiovascular system plays a crucial role in transporting these blood cells to various parts of the body once they are produced in the bone marrow.

So, while the skeletal system provides the site for hematopoiesis, the cardiovascular system is responsible for distributing the blood cells, making it the most closely associated system in this context.