Which of the following tools can be used to measure the turbidity of a liquid by measuring the transmission of light through the sample?

A. The browning of an apple slice is caused by the enzyme polyphenol oxidase, which is present in the apple, not the lemon juice.

B. This acidic environment can denature the polyphenol oxidase enzyme in the apple, rendering it inactive and thus preventing the browning reaction.

C. The browning is a result of a chemical reaction, and dilution would not prevent the reaction from occurring.

D. The browning is due to the formation of melanin, which are pigments resulting from the enzymatic reaction. Lemon juice's acidity affects the enzyme responsible for this reaction, not the pigments themselves.

A. Potassium, with an atomic number of 19, has one electron in its outermost shell. This makes it more likely to lose that electron to achieve a stable electron configuration, resulting in a positively charged ion or cation.

B. Oxygen, with an atomic number of 8, has six electrons in its outer shell. It is more likely to gain two electrons to fill its outer shell and become an anion, not a cation.

C. Helium, with an atomic number of 2, has a full outer shell of electrons, making it very stable and unlikely to form ions under normal conditions.

D. Fluorine, with an atomic number of 9, has seven electrons in its outer shell. It tends to gain one electron to complete its outer shell and become an anion, not a cation.

A. A pivot joint allows for rotational movement around a single axis. An example of a pivot joint is the atlantoaxial joint in the neck, which allows for the rotation of the head.

B. A hinge joint permits movement in one plane, much like the opening and closing of a door.

C. The elbow and knee joints are classic examples of hinge joints, allowing for flexion and extension.

D. Gliding joints, also known as plane joints, allow for sliding movements in multiple directions within a plane. These are found in areas like the carpals of the wrist, where small bones slide against each other to allow for a range of movements.

The hip joint is a ball-and-socket joint, which is characterized by a spherical end of one bone fitting into a cup-like depression of another bone. This structure allows for a wide range of motion, including flexion, extension, abduction, adduction, and rotation. The hip joint, specifically, is formed by the articulation of the head of the femur and the acetabulum of the pelvis. It is designed for stability and weight-bearing, making it one of the most stable joints in the human body. This type of joint is also found in the shoulder, where the humerus fits into the glenoid fossa of the scapula.

A. The alveoli are the tiny air sacs within the lungs where the exchange of oxygen and carbon dioxide takes place. In diseases like emphysema, the walls between the alveoli can be damaged, leading to fewer and larger air sacs instead of many tiny ones. This reduces the surface area for gas exchange, making it difficult for the body to get the oxygen it needs.

B. The trachea, or windpipe, is the main airway that leads to the lungs. While it is not directly involved in the gas exchange process, it does play a crucial role in providing a clear path for air to reach the respiratory structures deeper within the lungs.

C. The primary bronchi are the two main branches from the trachea that lead into each lung.

They are large airways that begin the process of directing air to the lungs' smaller passages but are not the sites of gas exchange.

D. The secondary bronchi, also known as lobar bronchi, are divisions of the primary bronchi that enter each lobe of the lungs. Like the primary bronchi, they are part of the airway system that conducts air to and from the gas exchange surfaces but are not themselves involved in the exchange of gases.

A. The myocardium, is the thick, muscular middle layer of the heart's walls and is responsible for the pumping action of the heart due to its contractile cardiomyocytes.

B. The pericardium is the fibrous sac that encloses the heart providing protection and anchoring the heart within the thoracic cavity.

C. The epicardium is the outermost layer of the heart wall, also known as the visceral layer of the serous pericardium, and it provides an additional layer of protection and contains the blood vessels and nerves that supply the heart tissue.

D. The endocardium is the thin inner lining of the heart chambers and also forms the surface of the valves. It is comprised of endothelial cells and a layer of subendocardial connective tissue, which is continuous with the connective tissue of the myocardium. This layer is essential for providing a smooth lining for the chambers of the heart and the heart valves, ensuring efficient blood flow and minimizing turbulence within the heart.

A. Plasma cells are specialized white blood cells that produce antibodies, which are proteins that can bind to and help neutralize pathogens like bacteria and viruses.

B. Helper T-cells play a crucial role in the immune system by activating and directing other immune cells, including B-cells to produce antibodies and cytotoxic T-cells to kill infected cells. They recognize foreign antigens presented by antigen-presenting cells and release cytokines that stimulate the immune response.

C. Cytotoxic T-cells, also known as killer T-cells, directly attack and destroy cells that have been infected by viruses or have become cancerous. They are part of the adaptive immune response and are important for eliminating intracellular pathogens.

D. Natural killer cells are a type of lymphocyte that can kill virus-infected cells and tumor cells without prior sensitization to them. They are part of the innate immune system and provide a rapid response to virally infected cells and a degree of immune memory.

A. Neuron cell axons are typically found in the white matter of the brain, as they are the long, slender projections of neurons that transmit electrical impulses away from the neuron's cell body to other neurons, muscles, or glands.

B. The meninges are the protective membranes that cover the brain and spinal cord, not the grey matter itself. They consist of three layers: the dura mater, arachnoid mater, and pia mater, which work together to protect the central nervous system and contain cerebrospinal fluid.

C. The corpus callosum is a thick band of nerve fibers that divides the cerebrum into left and right hemispheres and facilitates communication between the two sides of the brain. It is part of the white matter, not the grey matter.

D. Neuron cell bodies, also known as somas, are the parts of the neuron that contain the nucleus and most of the cytoplasm. They are responsible for maintaining the life of the neuron and are primarily located in the grey matter of the brain and spinal cord, where they process information received from the body's sensory systems or other neurons. Grey matter is a crucial component of the central nervous system and is primarily composed of neuronal cell bodies, neuropil, glial cells, synapses, and capillaries.

A. The fallopian tubes are not the source of menstrual blood and tissue. They are narrow tubes that connect the ovaries to the uterus and serve as the pathway for the egg (ovum) to travel during ovulation.

B. The uterine wall, specifically the inner lining, is the source of the blood and mucosal tissue shed during menstruation. Each month, the endometrium thickens in preparation for a potential pregnancy. If fertilization does not occur, this thickened lining is shed, resulting in menstrual bleeding.

C. The vagina, is the exit route for the menstrual flow but is not the source of the blood and tissue.

D. The ovaries, which produce eggs and hormones like estrogen and progesterone, are also not the source of menstrual blood and tissue. They are involved in the menstrual cycle by triggering the thickening of the endometrium, but the tissue itself originates from the uterine wall.

A. The excretory system is responsible for the removal of waste products from the body's metabolism, including the filtration and excretion of waste material from the blood by the kidneys.

B. The digestive system breaks down proteins into amino acids through the action of enzymes. Proteins are first denatured by stomach acid, then enzymes like pepsin begin the breakdown, which is continued in the small intestine by other enzymes such as trypsin and chymotrypsin.

C. The endocrine system consists of glands that secrete hormones into the bloodstream, which regulate processes such as growth, metabolism, and sexual development. It does not play a direct role in the breakdown of proteins into amino acids.

D. The circulatory system is responsible for the transportation of blood throughout the body, which includes nutrients, gases, and waste products, but it does not break down proteins into amino acids. This process is solely the function of the digestive system.

A. Brucellosis is an infectious disease caused by the bacteria Brucella, which is transmitted from animals to humans, primarily through the consumption of unpasteurized dairy products or undercooked meat from infected animals.

B. Psoriasis is a noninfectious disease. It is a chronic autoimmune condition that results in the rapid buildup of skin cells, leading to scaling on the skin's surface. Psoriasis is believed to result from an abnormal immune response and is not contagious.

C. Chikungunya is an infectious disease caused by the Chikungunya virus, which is transmitted to humans by mosquitoes. It is characterized by fever and severe joint pain but is not classified as a noninfectious disease.

D. Dengue is an infectious disease caused by the Dengue virus, spread by mosquitoes.

Symptoms include high fever, headache, and joint pains. It is not a noninfectious disease.