Which of the following is supported by the cell theory?

A. antibody

B. pathogen

C. trigger

D. vaccination

Pathogen is an infectious foreign body that enters the body and causes disease or illness to the person. There are five types of pathogens: viruses, bacteria, fungi, protozoa, and worms. Pathogens have antigen proteins found on their surface and are unique to each pathogen.

Antibody is a protein produced by the body’s immune system when it detects harmful substances (antigens). There are many different antibodies found in the body. Each one is unique and protects the body against the specific antigen that it detects at any given time. If there are no antibodies for a specific antigen, the more likely you are to develop an illness.

Vaccinations are the introduction of a dead or disabled pathogen or of a harmless microbe with the protein of a pathogen on its surface into the body. Often administered through needle injection, to stimulate the immune system to produce immunity to a specific disease Immunity protects the body from a disease when exposed to it.

There are four types of immunity: natural/passive, natural/active, artificial/passive, and artificial/ active.

• Natural/passive – Babies receive immunities from breastmilk.
• Natural/active – The body produces antibodies to combat an illness when a person becomes sick.
• Artificial/passive – This immunity is temporary and requires doses of serum to maintain the immunity.
• Artificial/active – A vaccination provides artificial/active immunity.

A. Saturated and homogeneous

B. Saturated and heterogeneous

C. Unsaturated and homogeneous

D. Unsaturated and heterogeneous

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. 

• A mixture is when elements and compounds are physically, but not chemically, combined.
• A homogeneous mixture is when substances mix evenly and it is impossible to see individual components. A heterogeneous mixture is when the substances mix unevenly and it is possible to see individual components.
• A solution is 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. An unsaturated solution has the ability to dissolve more solute and a saturated solution has already reached the limit of solute it can dissolve.

A. Sample size

B. Control group

C. Dependent variable

D. Independent variable

A control group is a factor that does not change during an experiment. Due to this, it is used as a standard for comparison with variables that do change such as a dependent variable.

Recall that these make up the scientific method, described below:

• Problem: The question created because of an observation. Example: Does the size of a plastic object affect how fast it naturally degrades in a lake?
• Research: Reliable information available about what is observed. Example: Learn how plastics are made and understand the properties of a lake.
• Hypothesis: A predicted solution to the question or problem. Example: If the plastic material is small, then it will degrade faster than a large particle.
• Experiment: A series of tests used to evaluate the hypothesis. Experiments consist of an independent variable that the researcher modifies and a dependent variable that changes due to the independent variable. They also include a control group used as a standard to make comparisons. 
  • Example: Collect plastic particles both onshore and offshore of the lake over time. Determine the size of the particles and describe the lake conditions during this time period.
• Observe: Analyze data collected during an experiment to observe patterns. 
  • Example: Analyze the differences between the numbers of particles collected in terms of size.
• Conclusion: State whether the hypothesis is rejected or accepted and summarize all results.
• Communicate: Report findings so others can replicate and verify the results.

A. Advancements in microscopy took place slowly.

B. Cells were difficult to isolate for experimental analysis

C. Researchers believed a cell formed from preexisting cells

D. Scientists already proved that cells were essential for life.

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.

A. carbon dioxide

B. minerals in soil

C. decaying matter

D. sugar molecules

Autotrophs are organisms that use basic raw materials in nature, like the sun, to make energy-rich biomolecules. Minerals are naturally inorganic.

Autotrophs are organisms that make energy-rich biomolecules from raw material in nature. They do this by using basic energy sources such the sun. This explains why most autotrophs rely on photosynthesis to transform sunlight into usable food that can produce energy necessary for life. Plants and certain species of bacteria are autotrophs.

A. Stomach

B. Esophagus

C. Oral cavity

D. Small intestine

The duodenum is the first part of the small intestines, located between the stomach and the middle part of the small intestines (jejunum). Once food has mixed with acid in the stomach, it moves into the duodenum, where it then mixes with bile from the gallbladder and digestive juices secreted from the pancreas. In the duodenum, absorption of vitamins, minerals, and nutrients begins.

A. leaves the aorta

B. fills the right atrium

C. reaches body tissues

D. flows through arteries

Blood continually flows in one direction, beginning in the heart and proceeding to the arteries, arterioles, and capillaries. When blood reaches the capillaries, exchanges occur between blood and tissues. After this exchange happens, blood is collected into venules, which feed into veins and eventually flow back to the heart’s atrium. The heart must relax between two heartbeats for blood circulation to begin.

Two types of circulatory processes occur in the body:

Systemic circulation

• The pulmonary vein pushes oxygenated blood into the left atrium.
• As the atrium relaxes, oxygenated blood drains into the left ventricle through the mitral valve. 3. The left ventricle pumps oxygenated blood to the aorta.
• Blood travels through the arteries and arterioles before reaching the capillaries that surround the tissues.

Pulmonary circulation

• Two major veins, the Superior Vena Cava and the Inferior Vena Cava, brings deoxygenated blood from the upper and lower half of the body.
• Deoxygenated blood is pooled into the right atrium and then sent into the right ventricle through the tricuspid valve, which prevents blood from flowing backward.
• The right ventricle contracts, causing the blood to be pushed through the pulmonary valve into the pulmonary artery.
• Deoxygenated blood becomes oxygenated in the lungs.
• Oxygenated blood returns from the lungs to the left atrium through the pulmonary veins.

A. Urinary system

B. Digestive system

C. Muscular system

D. Cardiovascular system

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.

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. 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.