Question

Fill in the blanks.

Answer 1

1. Parasites

2. herbivores

3. phagocytosis

4. Plant

5. oxygen (O2)

6. gills

7. open

8. urea

9. Single-loop circulatory systems have one direction of blood flow. Typically in fish, oxygen is absorbed in the gills, flows in blood to the body organs, and back to the heart, which pumps it directly back to the gills. In double-loop circulatory systems, the heart has multiples of each chamber. Part of the heart pumps blood to the lungs, to get oxygen. This blood flows back to a different chamber where it then gets pumped to the body. Once its oxygen has been used up, it goes back to the heart to be pumped all over again to the lungs.

10. Freshwater animals have lower water and higher salt concentrations than the environment in their cells. This means water constantly tries to diffuse into the animals, which can bloat them. They have special cell processes that remove extra water.

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