Flatworms absorb oxygen by diffusion mechanism through their
skin to the cells in their bodies. Since flatworms do not have a circulatory system,
their bodies' cells are positioned close to the skin to ease the uptake of
oxygen from surrounding fluids or water.
Answer:
Synonyms in the genetic code exist and some species only use one synonym to get the same amino acid. The reason why the percentage is low in gene is because it does not involve a lot of processes compared to the proteins which undergo mRNA and tRNA to be coded as amino acids.
Explanation:
<span>B. Inherited behaviors that allow animals to survive and reproduce will be spread throughout the population and can evolve by natural selection.</span>
