That they are <span>caused by microorganisms.</span>
Answer:
Nature
Explanation:
Because erosion happens in the nature.
A cell that just fertilized has to divide 6 times to form a 64 cell blastomere.
<u>Explanation:</u>
Human reproduction begins with the fusion of male gamete sperm and female gamete ovum. The fusion of sperm and ovum forms the zygote that is diploid. The zygote then undergoes mitotic division to develop into embryo.
The zygote first divides into two and the two individual cells divide again to form four individual cells and so on. Thus the number of cells after each division can be represented by the equation 
where n is the number of divisions. in the question it is given that the blastomere has 64 cells.
n=6
This means that the fertilized cell has to divide 6 times to develop into 64-celled blastomere.
STRUCTURAL FUNCTIONAL THEORY
<u>Explanation:</u>
The structural functional theory states that the gender inequalities are exist by this method and they create the new ways for the division of labor and the population is clearly responsible for the certain act of the labour in the social system.
The structural functionalism states that it is the building blocks of the society and the frame work for building for the social system which is more compile to perform and the together work promotes the stability. The social system causes the reality and the system parts are functionally correlated.
Highly developed sense organs that allow them to see, hear, feel, smell, and taste. They sense the very low levels of electricity emitted by other animals.
