20. One difference between a gastrovascular cavity and a one-way digestive system is the presence or absence of
a. cell specialization
b. digestive enzymes
c. digestion within body cells
d. a moist membrane for nutrient diffusion
A?
21. In an open circulatory system,
a. water is drawn into the mantle cavity to provide oxygen to body tissues
b. lungs branch into small tubules to provide oxygen to tissues
c. wastes are eliminated directly to the environment from tissues
d. body tissues are bathed directly in fluid containing oxygen
D?
22. The system that does not allow for direct contact between oxygen-carrying cells and tissues is called
a. a one-way digestive system
b. the excretory system
c. a closed circulatory system
d. an open respiratory system
C?
-MC
20. A is correct.
21. D is correct.
22. C is correct.
For question 20, the correct answer is c. digestion within body cells.
For question 21, the correct answer is d. body tissues are bathed directly in fluid containing oxygen.
For question 22, the correct answer is c. a closed circulatory system.
To find the answer to question 20, you need to understand the difference between a gastrovascular cavity and a one-way digestive system.
- A gastrovascular cavity is a digestive chamber that has only one opening for both the intake of food and the elimination of waste. Digestion occurs within the body cells, where food is broken down and nutrients are absorbed. Therefore, the presence or absence of digestion within body cells is the difference between a gastrovascular cavity and a one-way digestive system.
- On the other hand, a one-way digestive system has a separate mouth and anus, allowing for a unidirectional flow of food through the system. This type of digestive system typically involves the use of specialized digestive enzymes to break down food.
From this explanation, we can conclude that the correct answer to question 20 is c. digestion within body cells.
Now, let's move on to question 21. To get the answer, you need to understand the characteristics of an open circulatory system.
- In an open circulatory system, there is no distinction between blood and interstitial fluid. The body tissues are bathed directly in a fluid containing oxygen, which is commonly called hemolymph. Oxygen is transported and distributed to the tissues through the direct contact of the hemolymph with the tissues.
Based on this information, the correct answer to question 21 is d. body tissues are bathed directly in fluid containing oxygen.
Lastly, let's find the answer to question 22 by understanding the concept of a closed circulatory system.
- A closed circulatory system is a system where the transport of oxygen and other nutrients is accomplished through a network of blood vessels. In this system, oxygen is carried by specialized cells (red blood cells) that directly come into contact with the body tissues through the blood vessel walls. This allows for efficient and controlled delivery of oxygen to the tissues.
Given this information, the correct answer to question 22 is c. a closed circulatory system.
So, the correct answers are: 20. c. digestion within body cells, 21. d. body tissues are bathed directly in fluid containing oxygen, and 22. c. a closed circulatory system.