I think all of them are,polar bears have fur, penguins are suited for water and land, etc
The answer is #4. The first and second one involve acid, which is chemical weathering. The third one involves oxidation, which is a chemical process. The only mechanical process is option four.
<span>C. C6 H12 O6 + 6 O2 → 6 C O2 + 6 H2 O + energy </span>
I believe animals that possess homologous structures probably evolved from the same ancestor. Homologous structures are similar because of common ancestry. A homologous structure is an example of an organ or bone that appears in different animals, underlining anatomical commonalities demonstrating descent from a common ancestor.