Describe the stages of cellular development prior to tissue stages. Your response should be approximately one paragraph in length and include the key words: cleavage, morula, blastula, blastocoel.

Morula (cleavage stage) >> blastoderm (blastula surrounded by the blastocoel)

Explanation:

The morula is an early-stage embryo stage (3 to 4 days after fertilization). During this stage, the embryo is composed of a globular solid mass of 16 to 32 cells (i.e., blastomeres) that are formed by cleavage of the zygote. The morula stage precedes the blastocyst stage (4 to 5 days after fertilization), a distinctive stage of a mammalian embryo with over 100 cells. In the rest of the animals, it is referred to as a blastula. A blastoderm is a post-cleavage embryo consisting of a solid layer of epithelial tissue that makes up the blastula, which surrounds a fluid-filled cavity called the blastocoel.

the index of refraction of the second medium is higher. i just took the test trust me !

after receiving a stimus, the sensory receptors send(s) signals to the appropriate area of the body.  

the must be sensory neurons.  

hope its .