Answer: E) tight junctions
Explanation:
Tight joints act as barriers that regulate the circulation of water and solutes between the epithelial layers. Tight junctions are classified as a paracellular barrier, which is defined as having no directional discrimination, but movement is largely dependent on solute size and load.
... release of carbon dioxide into the atmosphere
Answer:
Four innovations are central nervous system, eyes, bilateral and hermaphrodites.
Explanation:
Innovations found in an ancient flatworm were the presence of central nervous system means head and a brain. The head had eyes which is the first in the animal world. Their body is bilateral means equally divided into two parts. They are also hermaphrodites means having male and female on a single organism which was not present at that time of animals.
The nutrients and waste exchange occur in the capillaries
