1. The muscular tube that connects the mouth to the stomach is called the:

A. Pharynx
B. Esophagus
C. Trachea
D. Larynx

Correct answer: B

Rationale: The correct answer is B: Esophagus. The esophagus is the muscular tube that connects the mouth to the stomach. It plays a crucial role in transporting food from the mouth to the stomach through peristaltic movements. The pharynx is the part of the throat that connects the mouth and nasal cavity to the esophagus and trachea. The trachea, also known as the windpipe, is responsible for carrying air to and from the lungs. The larynx, commonly known as the voice box, is involved in producing sound and protecting the trachea during swallowing. Therefore, the esophagus is specifically responsible for food transport from the mouth to the stomach.

2. Which sentence uses the passive voice correctly?

A. The letter was written by Mary.
B. John built the house.
C. She gave the flowers to him.
D. They were eating dinner.

Correct answer: A

Rationale: Option a clearly identifies the object (letter) acted upon and the agent (Mary) performing the action in the passive voice.

3. The inability of the kidneys to effectively filter waste products from the blood is called:

A. Dehydration
B. Kidney failure
C. Incontinence
D. Nephritis

Correct answer: B

Rationale: The correct answer is B: "Kidney failure." Kidney failure refers to the inability of the kidneys to effectively filter waste products from the blood, leading to a buildup of toxins in the body. Dehydration, option A, is the state of lacking adequate fluid in the body and is not specifically related to kidney function. Incontinence, option C, is the loss of bladder control and is unrelated to kidney filtration function. Nephritis, option D, specifically refers to inflammation of the kidneys and may not always result in complete kidney failure. Therefore, the most appropriate answer for the described scenario is B.

4. What is the molar mass of Ca(NO3)2?

A. 74.1 g/mol
B. 132.1 g/mol
C. 164.1 g/mol
D. 78.1 g/mol

Correct answer: b

Rationale: Calculate the molar mass: Ca(40.08) + 2N(14.01) + 6O(16.00) = 132.1 g/mol.

5. What is the scientific term for a broken bone?

A. Osteoporosis
B. Fracture
C. Sprain
D. Dislocation

Correct answer: B

Rationale: The correct answer is B: 'Fracture.' A fracture is the scientific term used to describe a broken bone. Osteoporosis (A) is a condition where bones become weak and brittle, increasing the risk of fractures. A sprain (C) is an injury to a ligament, not a bone. A dislocation (D) occurs when the bones in a joint are forced out of their normal position, but it is not the term for a broken bone.