Question

marine organisms whose internal salt concentration varies with that of their environment are examples of:
○ urea - concentrators.
○ osmoconformers.
○ ion - concentrators.
○ fresh - water organisms.
○ osmoregulators.
question 15
2 pts
15
the term endotherm refers to animals that are:
○ able to retain some of their metabolic heat.
○ commonly known as being \cold blooded.\
○ able to maintain a constant internal salt concentration and temperature.
○ unable to regulate their internal temperature in relation to the outside environment.

Explanation:

First Question (Marine Organisms)

• Urea - concentrators: These are organisms that concentrate urea, not related to matching salt concentration with the environment.
• Osmoconformers: By definition, osmoconformers are organisms whose internal salt concentration conforms (varies with) the salt concentration of their environment.
• Ion - concentrators: Focus on ion concentration, not matching the overall salt concentration of the environment.
• Fresh - water organisms: Live in fresh water, and their internal salt concentration is different from the fresh - water environment (they are osmoregulators in most cases), and this option is not about marine organisms matching environmental salt concentration.
• Osmoregulators: These organisms regulate their internal salt concentration to be different from the environment, not matching it.

• Able to retain some of their metabolic heat: Endotherms (like mammals and birds) generate heat metabolically and can retain it to maintain a stable internal temperature.
• Commonly known as being "cold - blooded": "Cold - blooded" refers to ectotherms, not endotherms.
• Able to maintain a constant internal salt concentration and temperature: Endotherms mainly focus on temperature regulation, and while they do regulate internal conditions, the key for endotherm definition is heat production/retention for temperature, not specifically salt concentration.
• Unable to regulate their internal temperature in relation to the outside environment: Endotherms can regulate their internal temperature independent of the outside environment, while ectotherms are more dependent.

Answer:

B. osmoconformers

Question 15 (Endotherm)