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 role does DNA play in evolution?

A. It stores genetic information that can be passed on to offspring.
B. It allows for mutations that can introduce new variations.
C. It regulates the expression of genes that influence traits.
D. All of the above

Correct answer: D

Rationale: A) DNA stores genetic information that is passed on from parents to offspring through the process of reproduction. This genetic information contains instructions for the development and functioning of an organism. It serves as the hereditary material that carries the blueprint for an organism's traits and characteristics, allowing for the transmission of genetic information from one generation to the next. B) DNA can undergo mutations, which are changes in the genetic sequence. These mutations can introduce new variations in the DNA, leading to genetic diversity within a population. These variations are essential for natural selection and adaptation to changing environments. C) DNA plays a crucial role in regulating the expression of genes. Gene expression determines which proteins are produced in an organism, influencing its traits and characteristics. By controlling gene expression, DNA contributes to the development and maintenance of an organism's traits. D) Therefore, DNA is involved in all of the above processes, making it a key factor in evolution by driving genetic variation, inheritance, and gene expression. The interplay of these functions allows for the diversity and adaptation of species over time, shaping the evolutionary process.

3. Bone is primarily composed of which of the following inorganic materials?

A. calcium
B. magnesium
C. collagen
D. potassium

Correct answer: A

Rationale: Bone is primarily composed of calcium, making up about 70% of its inorganic content. Calcium is essential for bone strength and structure, playing a key role in maintaining bone health. Choice B, magnesium, while important for bone health, is found in smaller amounts in bones compared to calcium. Choice C, collagen, is a protein and is a major organic component of bone, not an inorganic material. Choice D, potassium, is an essential mineral for various bodily functions but is not a primary inorganic material found in bones.

4. Where does sperm maturation take place in the male reproductive system?

A. Seminal vesicles
B. Prostate gland
C. Epididymis
D. Vas Deferens

Correct answer: C

Rationale: Sperm maturation occurs in the epididymis, a coiled tube located on the back of each testicle. In the epididymis, sperm gain motility and the ability to fertilize an egg. It serves as a storage site for mature sperm until ejaculation. The seminal vesicles and the prostate gland contribute fluids to semen, enhancing sperm viability and motility. The vas deferens is responsible for transporting mature sperm from the epididymis to the urethra during ejaculation, but it is not where sperm maturation takes place. Therefore, the correct answer is the epididymis.

5. In an experiment where five tropical plants are kept at varying humidity levels in a greenhouse for three months, while one plant is left outside in normal conditions, with plant height measured weekly, what serves as the control of the experiment?

A. Plant height for each tropical plant
B. The plant left outside in normal conditions
C. Humidity level readings in the greenhouse
D. Amount of time used to study plant height

Correct answer: B

Rationale: The correct answer is B. The plant left outside in normal conditions acts as the control in the experiment. It provides a standard reference point for comparison to assess the impact of the varying humidity levels on the growth of the tropical plants. Choice A is incorrect because it refers to the dependent variable being measured, not the control. Choice C is incorrect as humidity levels in the greenhouse are part of the experimental conditions, not the control. Choice D is incorrect as the time used for studying plant height is a parameter of the experiment and not the control.