What is the name of the genetic disorder caused by the presence of an extra chromosome 21?

A. Monosaccharides are composed of two sugar molecules while disaccharides are composed of a single sugar molecule.

B. Monosaccharides are simple sugars that cannot be further broken down into simpler sugars while disaccharides are composed of two simple sugars.

C. Monosaccharides are only found in plants while disaccharides are only found in animals.

D. Monosaccharides are used for energy storage while disaccharides are used for structural purposes.

Carbohydrates are one of the main types of biomolecules and are composed of monomers called monosaccharides. Monosaccharides are simple sugars that cannot be further broken down into simpler sugars. They are usually composed of 3 to 7 carbon atoms and have a general formula of (CH2O)n, where n is a number between 3 and 7. Examples of monosaccharides include glucose, fructose, and galactose.

When two monosaccharides are joined together by a glycosidic bond, they form a disaccharide. Disaccharides are composed of two simple sugars and can be broken down into their constituent monosaccharides by hydrolysis. Examples of disaccharides include sucrose, lactose, and maltose.

Option a) is incorrect because it describes the composition of a disaccharide, not a monosaccharide. Option

c) is incorrect because both monosaccharides and disaccharides can be found in both plants and animals.

Option d) is incorrect because both monosaccharides and disaccharides can be used for energy storage and

structural purposes, depending on their specific structure and function in the organism.

A. Innate immunity is present at birth and provides immediate, non-specific protection against pathogens while adaptive immunity is developed over time and provides specific protection against particular pathogens.

B. Innate immunity involves the recognition of specific pathogens while adaptive immunity involves the recognition of general paterns of pathogens.

C. Innate immunity involves the production of antibodies while adaptive immunity involves the activation of phagocytes.

D. Innate immunity is activated by the lymphatic system while adaptive immunity is activated by the circulatory system.

Innate immunity is the first line of defense against pathogens and is present at birth. It provides immediate, non-specific protection against a wide range of pathogens, including bacteria, viruses, and fungi. Innate immunity involves physical barriers, such as skin and mucous membranes, as well as cellular and molecular components, such as phagocytes and cytokines.

Adaptive immunity, on the other hand, is developed over time and provides specific protection against particular pathogens. It involves the recognition of antigens, which are specific components of pathogens, by immune cells called lymphocytes. The lymphocytes then produce antibodies that are specific to the antigens, allowing for a targeted response to the pathogen. This process takes time to develop, as the immune system needs to encounter the pathogen and mount a response.

Overall, innate immunity provides immediate, non-specific protection while adaptive immunity provides specific protection that is tailored to the particular pathogen. Both forms of immunity work together to protect the body against pathogens.

A. Movement of substances from an area of high concentration to an area of low concentration.

B. Movement of substances against a concentration gradient with the help of transport proteins.

C. Movement of water molecules from an area of high concentration to an area of low concentration through a selectively permeable membrane.

D. Movement of substances into a cell by engulfing them with the plasma membrane.

Osmosis is the process by which water molecules move across a selectively permeable membrane from an area of high concentration to an area of low concentration, in order to equalize the concentration of solutes on both sides of the membrane. Selectively permeable membranes allow only certain molecules to pass through, while preventing the passage of others.

In osmosis, the movement of water molecules is driven by the concentration gradient of solutes, which cannot pass through the membrane. If one side of the membrane has a higher concentration of solutes than the other, water molecules will move from the side with the lower concentration of solutes to the side with the higher concentration of solutes, in an atempt to dilute the solutes and equalize the concentration on both sides.

Osmosis is important in many biological processes, including the uptake of water by plant roots, the regulation of water balance in animal cells, and the preservation of food by adding salt or sugar to create a hypertonic environment that inhibits bacterial growth.

A. H2O

B. CO2

C. NaCl

D. C6H12O6

The chemical formula for water is H2O. It consists of two hydrogen atoms and one oxygen atom.

A. Brain

B. Heart

C. Liver

D. Skin

The largest organ in the human body by surface area is the skin. It covers the entire external surface of the body and has an average surface area of about 20 square feet in adults.

A. Density

B. Melting point

C. Boiling point

D. Reactivity with acid

Chemical properties are characteristics of a substance that describe its ability to undergo a chemical change or reaction with another substance.

Reactivity with acid is a chemical property because it describes how a substance will react with an acid to produce a new substance. Density, melting point, and boiling point are physical properties that describe how a substance behaves under certain conditions but do not involve a chemical change or reaction.

A. A physical change involves the rearrangement of atoms and molecules while a chemical change involves the formation of new substances with different chemical properties.

B. A physical change involves the change of one state of mater to another while a chemical change involves the change of one substance into another.

C. A physical change involves the breaking of chemical bonds while a chemical change involves the breaking of intermolecular forces.

D. A physical change involves the release of energy while a chemical change involves the absorption of energy.

A physical change is a change that affects the physical properties of a substance, but does not change its chemical identity. Physical changes include changes in state, such as melting or boiling, changes in shape or size, and changes in phase, such as the dissolution of a solid in a liquid. In a physical change, the atoms and molecules of the substance are rearranged, but no new substances are formed.

A chemical change, on the other hand, is a change that results in the formation of new substances with different chemical properties. Chemical changes involve the breaking of chemical bonds between atoms and the formation of new bonds to create new compounds. Chemical changes are usually accompanied by a change in color, the formation of a gas or a solid, or the release or absorption of energy.

Overall, the main difference between a physical change and a chemical change is that a physical change only affects the physical properties of a substance while a chemical change results in the formation of new substances with different chemical properties.

A. Solids have a definite shape and volume while liquids have a definite volume but no fixed shape.

B. Solids have no definite shape or volume while liquids have a definite volume and take the shape of their container.

C. Solids and liquids have the same physical properties.

D. Solids have a definite volume but take the shape of their container while liquids have a definite shape and volume.

The main difference between a solid and a liquid is their physical state and the way their particles are arranged. In a solid, the particles are tightly packed together and have a fixed position, which gives the solid a definite shape and volume. Solids are also characterized by their high density, low compressibility, and high thermal conductivity.

In contrast, the particles in a liquid are more loosely packed and can move around each other, which allows the liquid to take the shape of its container. Liquids have a definite volume but no fixed shape, which means they can be poured or spilled. Liquids also have a lower density than solids, are more compressible than solids, and have lower thermal conductivity than solids.

Option b) is incorrect because it describes the properties of a gas, not a liquid. Option c) is incorrect because solids and liquids have different physical properties. Option d) is incorrect because it describes the properties of a gas, not a liquid or a solid.

A. Melting ice

B. Burning wood

C. Cooking an egg

D. Dissolving sugar in water

Exothermic reactions are reactions that release energy in the form of heat, light, or sound. Burning wood is an example of an exothermic reaction because it releases heat and light. As the wood reacts with oxygen in the air, it undergoes a combustion reaction that releases energy in the form of heat and light. Melting ice is an endothermic reaction because it requires energy input to melt the solid ice into liquid water. Cooking an egg is a chemical reaction that involves denaturing the proteins in the egg, but it is not necessarily exothermic or endothermic. Dissolving sugar in water is also not an example of an exothermic reaction because it does not release energy in the form of heat, light, or sound.

A. Bronchi

B. Alveoli

C. Diaphragm

D. Trachea

Diaphragm is responsible for regulating breathing rate and depth. It is a dome-shaped muscle located at the

bottom of the chest cavity that contracts and relaxes to help move air in and out of the lungs.