In the Cnideria the ectoderm cells are important because they: a) are the first
ID: 87021 • Letter: I
Question
In the Cnideria the ectoderm cells are important because they: a) are the first specialized digestive cells b) function to organize the stimulus and the response c) are needed for reproduction d) form the first digestive organ. e) form the first real organ The evolution/development of the skeletal system is an example of the process of cellular specialization. This refers to the fact that a) all the ectoderm cells remain the same b) All cells derived from the endoderm secret collagen c) the cells of the endoderm form notochord d) genes are activated or suppressed in the cell form the original mesoderm causing them to become types of stem cells that produce the skeleton e) genes are not involved in this function.Explanation / Answer
88.b.Epidermis is derived from outer embryonic ectodermal layer. It contains following cells with different functions-
epithelio muscular cells(functions as muscles ), glandulo muscular cells (secretes a bubble of gas ,hydra becomes light weight and floats on the water) ,interstitial cells(undifferentiated totipotent cells), nerve cells , sensory cells (response and stimulus)and cnidocytes (specialized cells with numerous functions such as fighting from enemy,collection of food etc.)
89. d.Cell specialization is when a newly divided cell starts to change in shape, inner structure, cytoplasm and membrane composition so that it can carry out a specific function.In this process certain genes are activated and certain other genes are suppressed.