if a hard boiled egg is placed in a beaker of salt water then the egg will

HESI A2

HESI A2 Biology Practice Test

1. If a hard-boiled egg is placed in a beaker of saltwater, what will happen to the egg?

A. Expand because water will move into the egg
B. Shrivel because water will leave the egg
C. Remain the same
D. None of the above

Correct answer: B

Rationale: The correct answer is B. When a hard-boiled egg is placed in a beaker of saltwater, the egg will shrivel because water will leave the egg through osmosis. Osmosis is the movement of water from an area of lower solute concentration to an area of higher solute concentration, in this case, from the egg into the saltwater. The higher concentration of solute in the saltwater causes water to move out of the egg, leading to the egg shrinking or shriveling. Choices A, C, and D are incorrect because the egg will not expand, remain the same, or have an outcome different from shriveling when placed in a beaker of saltwater.

2. Which of the following are components of the endocrine system?

A. The pituitary gland
B. The thyroid gland
C. The adrenal glands
D. All of the Above

Correct answer: D

Rationale: The endocrine system comprises a network of glands that produce and release hormones to regulate bodily functions. The pituitary gland, thyroid gland, and adrenal glands are essential components of this system. The pituitary gland secretes various hormones that control other glands and some body functions. The thyroid gland regulates metabolism, growth, and energy levels by producing thyroid hormones. The adrenal glands produce hormones involved in stress response, metabolism, and immune function. Therefore, all of the above glands are integral parts of the endocrine system, making choice D the correct answer.

3. In order, from lower to upper, the layers of the atmosphere are:

A. Exosphere, thermosphere, mesosphere, stratosphere, troposphere
B. Troposphere, stratosphere, mesosphere, thermosphere, exosphere
C. Mesosphere, troposphere, stratosphere, thermosphere, exosphere
D. Thermosphere, troposphere, stratosphere, mesosphere, exosphere

Correct answer: B

Rationale: The correct order of the layers of the atmosphere, from lower to upper, is troposphere, stratosphere, mesosphere, thermosphere, exosphere. The troposphere is the lowest layer where weather phenomena occur. The stratosphere contains the ozone layer, which absorbs and scatters the solar ultraviolet radiation. The mesosphere is where most meteorites burn up upon entering the Earth's atmosphere. The thermosphere is characterized by high temperatures due to the absorption of solar radiation. The exosphere is the outermost layer where the atmosphere transitions into space. Therefore, option B is the correct sequence, as it reflects the ascending order of the Earth's atmospheric layers.

4. Which organism reproduces via spore formation?

A. Shelf fungus
B. Lemon tree
C. Smallmouth bass
D. Staphylococcus

Correct answer: A

Rationale: The correct answer is A, Shelf fungus. Shelf fungus reproduces via spore formation. Spores are tiny, reproductive cells that are released into the environment to be carried by air or water, allowing the fungus to spread and reproduce. The other choices are incorrect because Lemon tree reproduces via seeds, Smallmouth bass reproduce sexually through the fertilization of eggs by sperm, and Staphylococcus bacteria reproduce by binary fission, dividing into two identical daughter cells.

5. How many bones are included in the human skeletal system?

A. 412
B. 103
C. Over 300
D. 206

Correct answer: D

Rationale: There are 206 bones in the human skeletal system. This includes bones in the skull, spine, ribs, arms, legs, hands, and feet. The correct answer is 206 because that is the standard number of bones in an adult human body. Choices A, B, and C are incorrect as they do not reflect the accurate count of bones in the human skeletal system.