The numbers next to the question is the question number we are supposed to answer.
1)How do mangrove plants such as Avicennia obtain oxygen when their roots are buried in the mud?
Mangrove plants have breathing roots or aerial roots that would be out of the mud. There are a few types of aerial roots, which include Pneumatophores, Kneed Roots and Prop and Stilt Roots. Pneumatophores are roots that are able to grow vertically out of the other roots that are underground, allowing the root system to obtain oxygen for the plant. Kneed Roots are roots that grow along the ground, and would occasionally grow upwards and back down, which resembles a bent knee. Prop roots are roots that grow from the trunk of the tree and the lower branches towards the ground, and after the tree becomes older, the prop roots would support the tree even when the tree is not anchored onto the ground, when this happens, the prop roots would be called stilt roots. Plank roots are roots that grow along the ground, but also grow to be thinner and taller, exposing surface area.
5)Why can’t a saltwater fish survive in freshwater aquarium? What are the differences in pH between seawater and freshwater ponds
Saltwater fishes have high salt content in their body, so if they are put into freshwater, the salt will diffuse out of their bodies and they will die. For the freshwater fishes, if they are put into saltwater, too much salt will enter their body and they will die.