Q: Which of the following equations correctly represents osmolarity?

$$\text{Osmolarity} = \frac{\text{moles of solute}}{\text{litre of solution}}$$

Question 1

Which of the following best describes the main function of homeostasis in multicellular organisms?

Accepted Answer

To maintain a stable internal environment despite external changes.

Question 2

Which process is illustrated by the movement of water across a selectively permeable membrane from an area of low solute concentration to high solute concentration?

Accepted Answer

Osmosis

Question 3

A freshwater fish is placed in saltwater. What is the most likely outcome for its cells?

Accepted Answer

Cells will shrink due to water loss.

Question 4

Which of the following equations correctly represents osmolarity?

Accepted Answer

$$	ext{Osmolarity} = \frac{	ext{moles of solute}}{	ext{litre of solution}}$$

Question 5

Which nitrogenous waste is most energetically expensive to produce but conserves the most water?

Accepted Answer

Uric acid

Question 6

Which excretory structure is correctly matched with the organism in which it is found?

Accepted Answer

Protonephridia – planarian

Question 7

What is the primary effect of alcohol on water balance in the human body?

Accepted Answer

It inhibits the release of ADH, causing increased urine output.

Question 8

A person drinks a very large amount of water in a short period. What is the most immediate risk?

Accepted Answer

Hyponatremia

Question 9

Conn’s syndrome is caused by excess aldosterone secretion. What is the major symptom you would expect?

Accepted Answer

High blood pressure

Question 10

Which of the following best describes the role of the loop of Henle in the mammalian kidney?

Accepted Answer

It creates a concentration gradient in the medulla to allow water reabsorption.

Question 11

Which hormone is released in response to increased blood osmolarity and acts to conserve water in the kidneys?

Accepted Answer

Vasopressin (ADH)

Question 12

Which of the following is a correct sequence of events in the excretory process of the nephron?

Accepted Answer

Filtration → Reabsorption → Secretion → Excretion

Question 13

Which of the following best explains why marine bony fish drink seawater?

Accepted Answer

To replace water lost by osmosis to the environment

Question 14

Which of the following is a function of the Renin-Angiotensin-Aldosterone System (RAAS)?

Accepted Answer

Increase blood pressure by promoting sodium and water reabsorption

Question 15

Which adaptation allows tardigrades to survive extreme dehydration?

Accepted Answer

Anhydrobiosis

Question 16

Which of the following is true about osmoregulators?

Accepted Answer

They actively regulate internal osmolarity regardless of the environment.

Question 17

A cell placed in a hypotonic solution will:

Accepted Answer

Gain water and swell

Question 18

Which of the following is a direct consequence of the breakdown of proteins and nucleic acids in animals?

Accepted Answer

Production of nitrogenous wastes

Question 19

Which excretory system is most efficient for water conservation in terrestrial insects?

Accepted Answer

Malpighian tubules

Question 20

Which of the following best describes the effect of high blood pressure on kidney filtration?

Accepted Answer

It increases the rate of filtration.

Homeostasis and Excretory Systems in Animals

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