Answer:
Down (plumaceous), (insulation)
Tail (pennaceous), (flight)
Contour (plumaceous/pennaceous), (flight/insulation)
Bristle (pennaceous), (flight)
Filoplume (pennaceous), (flight)
Hope this helps! :)
Your answer should be tissues.
Answer is B. Pioneer communities contain few species, while climax communities have many species.
Pioneer species are the first species that start life in an area. Their growth is fast and soon replaced by next community. Whereas, climax communities are made of many species. They are stable is not replaced by any other community. They are supporting new life.
The different barriers that you have to go through are the different organs of the immune system. These are the lymphoid organs, thymus, and bone marrow. The secondary wall that you have to go through are the lymphatic tissues which include the lymph nodes, adenoids, skin, liver, tonsils, spleen, and the lymph vessels.
At all times, these systems work hand-in-hand so that the body can protect itself in order for it to survive
