Answer:
The question lacks options, the options are:
A) All cells contain a nucleus.
B) All cells come from other living cells
C) All living organisms are made of one or more cells.
D) Cells are the basic unit of structure and function of all living things.
The answer is A
Explanation:
In 1830's, three scientists named; Mattias Schleiden, Theodor Schwann and Rudolph Virchow contributed to describing the basic properties of the cell, which they proposed in their so named CELL THEORY. This widely accepted cell theory has three components:
All living organisms are made up of one or more cells.
Cells are the basic and fundamental unit of life
All existing cells come from cells that have previously existed.
It was not proposed that all cells have a nucleus
the genetic material housed inside the cell nucleus is packaged in into these organized bundles.
- chromosomes
yes, coral polyps are a keystone species. it would be a keystone species because it is important in order for the coral to thrive.
If the sperm cell fertilises the ovum, and implantation does not occur, then the corpus luteum degenerates and it turns into corpus albicans, stopping progesterone secretion. If fertilisation occurs and implantation also, the syncytiotrophoblast, the "root part" of the blastocyst (one of the early structures originated from the zygote), produces a hormone that is called <span>human chorionic gonadotropin (hCG). The hCG is what makes the corpus luteum keep secreting progesterone and maintain itself. The progesterone will then help keep the endometrium and, therefore, allow the development of the embryo to happen.</span>
