the outermost layer of the skin providing protection against pathogens and the environment is the

ATI TEAS 7

TEAS 7 science practice

1. Which of the following is the outermost layer of the skin, providing protection against pathogens and the environment?

A. Dermis
B. Epidermis
C. Hypodermis
D. Stratum corneum (part of the epidermis)

Correct answer: B

Rationale: The epidermis is the correct answer as it is the outermost layer of the skin, providing protection against pathogens and the environment. It consists of multiple layers, including the stratum corneum, which is the outermost layer of the epidermis. The dermis is located beneath the epidermis, offering structural support and housing blood vessels, nerves, and glands. The hypodermis is the deepest layer of the skin, made up of fat and connective tissue that secures the skin to underlying structures. Choice A, Dermis, is incorrect as it is located beneath the epidermis. Choice C, Hypodermis, is incorrect as it is the deepest layer of the skin, not the outermost. Choice D, Stratum corneum (part of the epidermis), is not the correct answer as it is a specific layer within the epidermis and not the overall outermost layer of the skin.

2. What is the main function of dietary fiber in the digestive system?

A. To provide energy
B. To break down fats
C. To promote gut bacteria growth
D. To aid in absorption of nutrients

Correct answer: C

Rationale: Dietary fiber refers to the indigestible portion of plant foods that passes relatively intact through the digestive system. While fiber does not directly provide energy to the body, it plays a crucial role in promoting the growth of beneficial gut bacteria. These bacteria help in the fermentation of fiber, producing short-chain fatty acids that can be used as an energy source by the body. Additionally, fiber aids in regulating bowel movements, maintaining gut health, and supporting overall digestive function. The functions described in the incorrect choices do not align with the primary role of dietary fiber in the digestive system. Choice A is incorrect because fiber itself is not a direct energy source. Choice B is incorrect as fiber does not break down fats. Choice D is incorrect because while fiber affects nutrient absorption indirectly by supporting gut health, its primary role is not to aid in the absorption of nutrients.

3. What is the purpose of a catalyst?

A. To increase a reaction rate by increasing the activation energy
B. To increase a reaction rate by increasing the temperature
C. To increase a reaction rate by decreasing the activation energy
D. To increase a reaction rate by decreasing the temperature

Correct answer: C

Rationale: The purpose of a catalyst is to increase a reaction's rate by decreasing the activation energy required for the reaction to occur. This allows the reaction to proceed more quickly without being consumed in the process. The catalyst provides an alternate mechanism with a lower activation energy, making it easier for the reactants to convert into products. Choice A is incorrect because a catalyst lowers, not increases, the activation energy. Choice B is incorrect because a catalyst does not affect the temperature directly but provides an alternative pathway for the reaction to occur more easily. Choice D is incorrect because a catalyst does not lower the temperature but facilitates the reaction by lowering the activation energy barrier. Therefore, the correct answer is C, 'To increase a reaction rate by decreasing the activation energy.'

4. What is the difference between constructive and destructive interference of waves?

A. They have different effects on wave amplitude.
B. Constructive interference increases amplitude, while destructive interference decreases it.
C. They affect wave amplitudes differently depending on the wave type.
D. Their impact is determined by the relative phase of the waves, not wave speed or amplitude.

Correct answer: B

Rationale: Constructive interference and destructive interference are two phenomena that occur when waves interact. Constructive interference leads to an increase in wave amplitude when two waves meet in phase, resulting in the alignment of peaks and troughs. This alignment results in the combined wave having a higher amplitude. On the other hand, destructive interference causes a decrease in amplitude as two waves meet out of phase, leading to their cancellation. When peaks align with troughs, they cancel each other out, resulting in a lower overall amplitude. This difference in effect on wave amplitude distinguishes between constructive and destructive interference. Choice A is incorrect because it does not specify the direction of change in amplitude for each type of interference. Choice C is incorrect as both constructive and destructive interference can occur in various types of waves, not affecting them differently based on wave type. Choice D is incorrect because while the relative phase of waves does determine the interference type, it is the amplitude that is affected by constructive and destructive interference, not the wave speed.

5. How are the motor pathways of the ANS arranged?

A. Single neuron from CNS to target organ
B. Two neurons, a pre-ganglionic and post-ganglionic neuron
C. Multiple neurons from CNS to target organ
D. Single neuron from CNS to peripheral ganglia

Correct answer: B

Rationale: The correct answer is B. The motor pathways of the autonomic nervous system (ANS) are organized with two neurons: a pre-ganglionic neuron that transmits the signal from the central nervous system (CNS) to a ganglion, and a post-ganglionic neuron that conveys the signal from the ganglion to the target organ. This dual-neuron pathway enables the integration and modulation of signals before reaching the target organ, allowing for a more sophisticated and adaptable control system. Choice A is incorrect as it describes a single neuron pathway, which is not characteristic of ANS motor pathways. Choice C is incorrect as it suggests multiple neurons from the CNS to the target organ, which is not the typical arrangement. Choice D is incorrect as it describes a single neuron pathway from the CNS to peripheral ganglia, which does not account for the ganglionic transmission in ANS motor pathways.