A researcher wants to gather data on the average wing strength of all birds found in the American Northwest. The researcher only has one small net, so all large birds were excluded from the study. The researcher's results were different than expected, but he believes his data include enough birds to estimate the strength of all birds. For which of the following reasons should this data be rejected?

A. It gained an electron

B. It lost an electron.

C. It lost a proton.

D. It gained a proton.

A chloride ion has a negative charge because it gained an electron. When an atom gains an electron, it becomes negatively charged because it now has more electrons than protons. In the case of a chloride ion, the neutral chlorine atom gains an electron to become a negatively charged chloride ion.

The other options are incorrect because they do not result in a negative charge. Losing an electron would result in a positive charge. Losing or gaining a proton would change the identity of the atom and is not related to the formation of a chloride ion.

A. Veins

B. Arteries

C. Lacteal vessels

D. Interstitial spaces

The correct answer is c. Lacteal vessels. Lipids absorbed in the small intestine will first enter lacteal vessels, which are small lymphatic vessels located in the villi of the small intestine. These vessels transport the absorbed lipids to the lymphatic system, where they eventually enter the bloodstream.

a. Veins and b. Arteries are blood vessels that transport blood throughout the body. Lipids absorbed in the small intestine do not directly enter these vessels.

d. Interstitial spaces are spaces between cells and tissues that contain interstitial fluid. Lipids absorbed in the small intestine do not directly enter these spaces.

A. Centrifuge

B. Spectrophotometer

C. Microdensitometer

D. Electrophorometer

The correct answer is b. Spectrophotometer. A spectrophotometer is a tool that can be used to measure the turbidity of a liquid by measuring the transmission of light through the sample. Turbidity is a measure of the cloudiness or haziness of a liquid caused by the presence of suspended particles. A spectrophotometer measures the amount of light that passes through the sample and compares it to the amount of light that passes through a reference sample to determine the turbidity.

a. A centrifuge is a tool used to separate components of a mixture based on their densities, not to measure

turbidity.

c. A microdensitometer is a tool used to measure the optical density of an image, not to measure turbidity.

d. An electrophorometer is a tool used to separate charged particles based on their size and charge, not to measure turbidity.

A. Stomach

B. Spleen

C. Kidney

D. Gallbladder

The organ that filters excess solutes from the blood is the kidney ¹. The kidneys are a pair of bean-shaped organs located on either side of the spine, just below the rib cage ². They are responsible for filtering waste products and excess fluid from the blood and excreting them in the form of urine ².

The other options are not correct because they do not accurately describe the organ that filters excess solutes from the blood. The stomach, spleen, and gallbladder do not filter excess solutes from the blood.

A. Oxygen

B. Carbon monoxide

C. Carbon dioxide

D. Carbonic acid

The correct answer is d. Carbonic acid. When blood pH rises, carbonic acid can donate H+ ions to act as a buffer and help maintain the pH within a normal range. Carbonic acid is formed when carbon dioxide dissolves in water and reacts with it.

A. Oxygen is not responsible for donating H+ ions to act as a buffer when blood pH rises.

B. Carbon monoxide is a toxic gas that does not play a role in buffering blood pH.

C. Carbon dioxide can dissolve in water to form carbonic acid, which can then donate H+ ions to act as a buffer.

A. Removal of oxygen

B. Addition of carbon

C. Addition of neutrons

D. Removal of electrons

An oxidation reaction occurs when there is a removal of electrons ¹. Oxidation is the loss of electrons during a reaction by a molecule, atom or ion ¹. When oxidation occurs, the oxidation state of the chemical species increases ¹.

The other options are not correct because they do not accurately describe what occurs in an oxidation reaction. Removal of oxygen, addition of carbon, and addition of neutrons are not processes that occur in an oxidation reaction.

A. Pineal gland

B. Parathyroid gland

C. Parotid gland

D. Pituitary gland

The parotid gland is an exocrine gland that secretes saliva into the mouth. Exocrine glands secrete their products into ducts that carry the secretions to the body's surface or into body cavities. The other options are endocrine glands, which secrete hormones directly into the bloodstream. The pineal gland secretes melatonin, the parathyroid glands secrete parathyroid hormone, and the pituitary gland secretes several hormones that regulate various bodily functions.

A. Motor neuron

B. Interneuron

C. Sensory neuron

D. Neuroglia

An efferent neuron that is responsible for releasing a neurotransmitter that stimulates a muscle cell to contract is a motor neuron ². Motor neurons carry signals from the brain to the peripheral nervous system in order to initiate an action. The neurotransmitter acetylcholine (ACh) is released by motor neurons at the neuromuscular junction in skeletal muscle, causing the muscle to contract ³.

The other options are incorrect because they do not accurately describe the type of neuron responsible for releasing a neurotransmitter that stimulates a muscle cell to contract. Interneurons are found within the central nervous system and facilitate communication between sensory and motor neurons. Sensory neurons carry information from sensory receptors to the central nervous system. Neuroglia are support cells for neurons and do not transmit nerve impulses.

A. Develops into any kind of cell

B. Fights infectious diseases

C. Aids in the maturation of sex cells

D. Carries electrical impulses

The function of a totipotent cell is to develop into any kind of cell ¹. Totipotent cells have the capacity to produce all adult cell types and can enter the germ line, contributing genetic material to succeeding generations ?. They have the ability to self-replicate, producing daughter cells that are identical to the parent ?.

The other options are incorrect because they do not accurately describe the function of a totipotent cell. Fighting infectious diseases, aiding in the maturation of sex cells, and carrying electrical impulses are not functions performed by totipotent cells.

A. The inhibition of sodium and potassium pumps, stopping all ion movement into the neuron

B. The opening of sodium channels, allowing sodium to enter the neuron

C. The closing of both sodium and potassium channels to restrict movement of ions into and out of the neuron

D. The opening of potassium channels allowing potassium to leave the neuron

D. The opening of potassium channels allowing potassium to leave the neuron

The correct answer is d. The opening of potassium channels allowing potassium to leave the neuron. Repolarization of a neuron occurs after an action potential, when the neuron's membrane potential returns to its resting state. This is achieved by the opening of potassium channels, which allows potassium ions to flow out of the neuron. This movement of positively charged ions out of the neuron helps to restore the negative membrane potential.

A. The inhibition of sodium and potassium pumps would not allow for repolarization because these pumps are necessary for maintaining the resting membrane potential.

B. The opening of sodium channels would cause depolarization, not repolarization.

C. The closing of both sodium and potassium channels would restrict ion movement, but it would not allow for repolarization.