Which description best defines blastocyst?
a)a fertilized egg
b)an egg released from the ovary
c)a mass of specialized cells
d)an embryo with a notochord

The correct answer is option C

Blastocyst can be defined as a mass of specialized cells that has gone through differentiation and this structure is formed after the 5 days from of fertilization. The fluid filled cavity opens up into morula which looks like a ball of cells. This structure is formed as an early development of the mammals. It almost looks like a cluster of cells.

hormones in blood stream

image: dtc.ucsf.edu

endocrine glands secrete hormones into the blood stream near them; the hormones then travel in our bloodstream until it reaches its destination, called a target cell, in distance parts of the body. in the target tissue, hormones lock onto the target’s plasma membrane, called the receptor site.

i think that d. wind is the answer.   i missed the question when i answered a. currents.