Hormone is a substance that directly involved in cellular communication within the human body.
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Explanation:
Biosphere. It is the highest level of organization. It is the global ecological system which consists of all the living organisms and other factors which supports life.
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.
Explanation:
Chemical digestion is a vital part of the digestive process. Without it, your body wouldn't be able to absorb nutrients from the foods you eat. While mechanical digestion involves physical movements, such as chewing and muscle contractions, chemical digestion uses enzymes to break down food. Make my inbox healthier.
Answer:
Spinal cord
Explanation:
The PNS consists of the nerves and ganglia outside the brain and spinal cord.