You Are Conducting an Experiment by Trying to Reproduce the Work

question 16

Multiple Choice

You are conducting an experiment by trying to reproduce the work performed in 1891 by Hans Driesch, a German embryologist. Working with a fertilized sea urchin egg, you allow it to complete the first cell division after fertilization. You then carefully separate the two cells of the embryo and allow their development to continue. Based on Driesch's experiment, which result below would you expect to happen?

• A)Both of the cells will die.
• B)Both of the cells will develop into complete and normal embryos.
• C)One cell will develop into a normal, though smaller, embryo; the other dies.
• D)One cell will develop into half an embryo; the other will develop into the other half of the embryo.
• E)One cell will develop into a defective embryo and the other will die.

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Definitions:

Holothuroidea

Holothuroidea, commonly known as sea cucumbers, are echinoderms with elongated bodies and leathery skin, representing a major group of the phylum Echinodermata.

Tunicates

Chordates belonging to subphylum Urochordata; sea squirts.

Tadpoles

The aquatic larval stage of amphibians, especially frogs and toads, characterized by gills, a tail, and a later transition to the adult form.

Tunic

In a biological context, a fibrous or cellular covering layer, such as that surrounding certain seeds or the body of sea squirts and other invertebrates.