Answer:
B. often use tube feet to move around in their environment
Explanation:
Tube feet are tiny tubular projections of echinoderms on the underside (oral side). They are a member of the echinoderm water vascular system.
Tubular feet are used for feeding, breathing and shifting. They are arranged around the sides, in grooves. They work by hydraulic pressure. They are used to transfer food in the centre to the oral mouth, and may stick to surfaces. Tube feet allow certain animals to stick and travel slowly to the ocean floor. for example starfish uses tube feet for the above functions.
Hence, the correct option is B.
Explanation: One of the highest probabilities is because of the bird in the front (the one in the point of the v) takes the command in leading to others in the flock to there location which explains for that as in there is no new members of there flock doing so.
Another reason could be is air resistances and helps the flock fly.
The primary function of all lymph nodes is the production of lymphocytes, which help defend the body against microorganisms and against harmful foreign particles and debris from lymph before it is returned to the blood stream. The major clusters of lymph nodes are in six areas.
Sponges are sessile animals that have specialized cells called amoebocytes and choanocytes.
Sponges (phylum Porifera) are one of the simpllest multicellular organisms (first to branch off the evolutionary tree from the common ancestor of all animals) that have bodies full of pores and channels allowing water to circulate through them. Sponges’ s structure consists of two thin layers of cells and mesohyl layer between them. They don’ t have real tissues or organ systems such as nervous, digestive or circulatory systems. Constant water flow through their openings and pores obtain food and oxygen and remove wastes.
