1. The term "double circulation" in the cardiovascular system refers to

A. The separation of oxygenated and deoxygenated blood flow within the heart.
B. The regulation of blood pressure through vasoconstriction and vasodilation
C. The cyclic contraction and relaxation of the heart muscle.
D. The existence of two separate circulatory pathways, one for the lungs and one for the body.

Correct answer: D

Rationale: The term 'double circulation' in the cardiovascular system refers to the existence of two separate circulatory pathways, one for the lungs (pulmonary circulation) and one for the body (systemic circulation). In pulmonary circulation, deoxygenated blood is pumped from the heart to the lungs to pick up oxygen and release carbon dioxide. Then, oxygenated blood returns to the heart to be pumped out to the rest of the body in systemic circulation. This separation of oxygenated and deoxygenated blood flow in different pathways is what distinguishes the double circulation system. Therefore, option D is the correct answer as it accurately describes the concept of double circulation in the cardiovascular system.

2. What is the CRISPR-Cas9 system used for in gene editing?

A. To amplify specific DNA sequences.
B. To cut DNA at specific locations.
C. To deliver genes into cells.
D. To sequence entire genomes.

Correct answer: B

Rationale: Rationale: The CRISPR-Cas9 system is a powerful tool used in gene editing to precisely target and cut DNA at specific locations within the genome. This system consists of a guide RNA that directs the Cas9 enzyme to the desired DNA sequence, where it creates a double-strand break. This break can then be repaired by the cell's natural DNA repair mechanisms, allowing for the introduction of specific genetic modifications. Options A, C, and D do not accurately describe the primary function of the CRISPR-Cas9 system in gene editing.

3. A solution is 60% alcohol. If 200ml of the solution are used, how much pure alcohol is present?

A. 100ml
B. 120ml
C. 140ml
D. 160ml

Correct answer: C

Rationale: Multiply the total solution volume (200ml) by the alcohol percentage (60%)

4. A patient's oxygen flow rate is set at 4 liters per minute. How many cubic centimeters of oxygen are delivered per minute?

A. 400 cubic centimeters
B. 4,000 cubic centimeters
C. 40,000 cubic centimeters
D. 400,000 cubic centimeters

Correct answer: B

Rationale: Remember 1 liter is equal to 1000 cubic centimeters. Multiply the flow rate in liters per minute by the conversion factor: 4 liters/minute * 1000 cmÂ³/liter = 4,000 cubic centimeters/minute.

5. Which organ is responsible for filtering blood and removing waste products?

A. Liver
B. Kidneys
C. Spleen
D. Pancreas

Correct answer: B

Rationale: The correct answer is B: Kidneys. The kidneys are responsible for filtering blood and removing waste products from the body through the production of urine. The liver plays a role in detoxifying the blood and producing bile, while the spleen is involved in filtering blood and removing old or damaged red blood cells. The pancreas is primarily responsible for producing digestive enzymes and regulating blood sugar levels. Therefore, the kidneys are the specific organ dedicated to the filtration of blood and removal of waste products, making them the correct choice in this question.

6. Homologous structures are those that:

A. Have the same function but different origins
B. Have different functions but the same origin
C. Are similar in appearance and function due to shared ancestry
D. Are identical in both appearance and function

Correct answer: C

Rationale: Rationale: - Option A is incorrect because structures with the same function but different origins are analogous structures, not homologous structures. - Option B is incorrect because structures with different functions but the same origin are also not homologous structures; they are considered to be vestigial structures. - Option D is incorrect because structures that are identical in both appearance and function are not necessarily homologous; they could be the result of convergent evolution. Homologous structures are those that share similarities in appearance and function due to being inherited from a common ancestor. These structures may have undergone modifications over time to adapt to different functions in different species, but their fundamental similarities can be traced back to a shared evolutionary history.