Answer:
- A Tongue-shaped structure called radula for grasping food --> Mollusca
- Fleshy lobe-like structure called parapodia --> Annelida
- Spongin fibers or spicules for support ---> Porifera
Explanation:
Radula: This is an organ used in feeding by mollusks. It constitutes a highly developed feeding organ. The radula has is conformed of small teeth-like structures located in rows. Lateral teeth vary in shape and size. The movements of the radula during feeding are complexes acting as a scratcher on the surface to get the food.
Parapodia: These are characteristic lateral appendixes that emerge and extend from each of the body segments of invertebrates such as polychaetes. The typical parapodium is a fleshy prolongation more or less laterally comprised and is composed of a superior branch (notopodium) and an inferior branch (parapodium).
Spicules: Sponges (Poriferous) skeleton is composed of calcium carbonate and siliceous micro-structures called spicules. Their morphology is so varied that it is used in taxonomy for identification and classification.
There are different kinds of spicules:
- Monoaxonic spicule: needle-shaped, straights or curves
- Tetraxonic spicules: they have four prolongations
- Triaxonic or Hexaxonic spicules
- Poliaxonic spicules
Two terms can be applied to any of these spicules kinds:
- Megaspicules: They are elongated and compose the main architecture of the sponge skeleton
- Microspicules: Variable in shape and size, with ancillary functions
Sponges have few predators because of the spicule structures and their high toxicity. Many of them are capable of perforating soft tissues and producing urticant substances.
Syphilis is transmitted through sexual actions through small cuts, for malaria, it would have to be through mixing of blood from a contaminated source to a uncontaminated source.
It's A. Primary succession :) because Human economics and ecology are linked together because human economics utilizes the ecosystem and the natural resources in older for economics to actually exist. :)))))))
