ati teas 7 science

Correct Answer: A

Rationale: The correct answer is A: Solid. Solids have both a definite volume and a definite shape because the particles are tightly packed and vibrate in fixed positions. This leads to a rigid structure and minimal movement, maintaining the shape and volume. In contrast, liquids (B) have a definite volume but take the shape of their container, gases (C) have neither a definite shape nor volume as they expand to fill the container, and plasmas (D) have no definite shape or volume due to their high energy state.

Correct Answer: B

Rationale: The correct answer is B: Cardiac muscle. Cardiac muscle is found exclusively in the heart, allowing it to contract rhythmically and involuntarily to pump blood throughout the body. Smooth muscle (A) is found in organs like the intestines and blood vessels, not in the heart. Skeletal muscle (C) is attached to bones and responsible for voluntary movements, while voluntary muscle (D) is a general term that refers to skeletal muscle controlled voluntarily. Therefore, the unique characteristics of cardiac muscle make it the correct answer for this question.

Correct Answer: C

Rationale: The correct answer is C: Holding urine in the bladder for long periods is NOT recommended for optimal urinary system health. When urine is held for a long time, it can increase the risk of urinary tract infections and bladder issues. It can also lead to bladder distension and potential damage to the bladder muscles. To maintain urinary system health, it is crucial to empty the bladder regularly to prevent bacterial growth and support proper bladder function. Choices A, B, and D are recommended practices for optimal urinary system health. Limiting high-sodium foods helps reduce the risk of kidney stones and hypertension, consuming cranberry juice can help prevent urinary tract infections, and regular moderate-intensity exercise promotes overall health, including the urinary system.

Correct Answer: B

Rationale: The correct answer is B: Ball-and-socket joint. This joint allows for the greatest range of motion due to its structure, where a rounded bone fits into a cup-like socket, enabling movement in multiple directions. This design permits flexion, extension, abduction, adduction, and rotation, providing a wide range of motion compared to other joint types. A: Hinge joints allow movement in one plane (like the elbow or knee). C: Pivot joints allow rotation around a central axis (like the neck). D: Saddle joints have more limited motion (like the thumb).

Correct Answer: A

Rationale: The correct answer is A: Calcitonin. Calcitonin is produced by the thyroid gland and functions to lower blood calcium levels by promoting calcium deposition in bones and inhibiting calcium reabsorption in the kidneys. This hormone opposes the action of parathyroid hormone (PTH), which increases blood calcium levels by promoting calcium release from bones and increasing calcium reabsorption in the kidneys. Thyroxine is a thyroid hormone that regulates metabolism and growth, not calcium levels. Insulin is a hormone produced by the pancreas that regulates blood sugar levels, not calcium levels. Thus, A is the correct answer as it directly regulates calcium levels in the blood through its actions on bones and kidneys.