What is the portion of the cell cycle during which the chromosomes are invisible under the light microscope because they are not yet condensed

Interphase

Explanation:

The portion of the cell cycle during which the chromosomes are invisible under the light microscope is the interphase.

Generally, there are 2 main phases of the cell cycle, namely;

1. The interphase

2. The m phase

The interphase is further subdivided into 3 phases:

The m phase represents the active division phase, also known as mitosis.

Immediately the cell leaves the interphase for the  m phase, the genetic materials in the cell condense, thicken, and become visible under the microscope as chromosomes. This phase of mitosis is known as the prophase and the chromosomes remain visible through the rest of the mitotic phase (metaphase, anaphase) until the last phase, which is the telophase/cytokinesis.

At telophase/cytokinesis, the chromosomes condense back and the daughter cells produced enters the interphase for a repetition of the cycle.

"menstrual cycle is a complex cycle that consists of several processes. order of occurrence of steps in menstrual cycle are as follows:

1. high progesterone levels maintain the endometrium lining of the uterus.

2. endometrium lining breaks down and low levels of estrogen stimulate the pituitary to release fsh and lh.

3. fsh and lh stimulates the follicles to develop and the oocyte to produce estrogen.

4. rising estrogen levels suppress fsh production and development of other follicles.

5. a spike in lh causes follicle to rupture.

6. a breakdown of corpus luteum causes progesterone level to drop."

if your own plato the answer is b. the fern transitioned from sporophyte generation to gametophyte generation.