IDRK
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Cellular differentiation is the process that results in the formation of more specialized cells that are ought to perform specific function in the body. Undifferentiated cells tend to perform more than one function like stem cell. Example of differentiated cell is liver cell, heart cell etc.
Differentiation process occurs many time during the growth of the organism to form organs and hence, organ system. Differentiation is a must process for the full development of an organism.
It is a scientific law
Explanation:
A scientific law states a constant relationship between two or more variables, each of which represents a property or measurement of specific systems. It is a constant and unchanging rule, usually expressed mathematically which allows to predict the unknown based on what is known with logical and real relationships.
A scientific theory is a set of concepts and rules (scientific laws) that express the relationships between observations of such concepts and generates a principle or set of principles to explain a phenomenon.
Answer:
A. Menstruation and the estrogen surge
Explanation:
The events that occur simultaneously in the monthly female reproductive cycle are menstruation and estrogen increase.
The menstrual cycle lasts about 28 days and is controlled by the secretion of gonadotropins (FSH and LH), secreted by the pituitary, and estrogen and progesterone, produced by the ovaries. The first day of the cycle corresponds to the first day of menstruation. During menstruation, levels of sex hormones in the blood are low. By the sixth day, the pituitary again secretes a greater amount of follicle stimulating hormone (FSH).
Therefore, in this first phase of menstruation, the pituitary secretes the hormone FSH, which, as the name implies, will stimulate the development of ovarian follicles. In turn, the follicles produce estrogen, which stimulates the growth of cells in the uterine inner wall, the endometrium, which becomes thicker and well-vascularized. These are changes that prepare the uterus for the implantation of an embryo, ie a pregnancy.
The high concentration of estrogen in the blood stimulates the secretion of luteinizing hormone (LH). LH induces ovulation, which occurs around the 14th day of the cycle. Next, the LH induces the rupture of the ovarian follicle and the consequent release of the egg, besides leading to the development of the corpus luteum. The corpus luteum produces progesterone, which will assist in maintaining the endometrium until the end of the menstrual cycle.