<span>The spicules have an important purpose for loosely constructed animal such as sponge. First of all, spicules give structure which is vital due to loose construction. Secondly, it protects from predators. This is similar to porcupine quills in serving to protect.</span>
a cell is the smallest structural and functional unit of an organism
A) a common ancestor
Homologous structures are structures that are similar in related organisms. There is a basic pattern of bones which can be inherited from a common ancestor
Answer:Greenhouse gases allow thermal energy to pass through the atmosphere and back out into space
Explanation:
Chemical digestion involves breaking down the nutrients into smaller cells
Physical digestion is using physical movements such as chewing and swallowing
