A particular mutation in a species of plant leads to variegation in its leaves (part of each leaf is white, while part is green). A plant breeder takes pollen from a green plant and pollinates a variegated plant. All resulting offspring are variegated. The breeder then takes pollen from a variegated plant and pollinates a green plant. All resulting offspring are green. What is going on?\

In the first case the male plant is green and the female plant is variegated. Their progeny consists of only variegated plants.

In the second case the male plant is variegated and the female plant is green. Their progeny consists of only green plants.

It can be observed that the progeny always shows the leaf color phenotype of the female parent. This is a case of maternal inheritance. After fertilization, the embryo has mitochondria and chloroplast from the female parent. This happens because the male gamete is very small and devoid of any organelle whereas the female gamete is big and carries its organelles. Out of all the organelles in female gamete, mitochondria and chloroplast have their own DNA.

Here, the gene for leaf color is probably located on chloroplast's DNA since it contains chlorophyll which is responsible for leaf color. If the female parent has green leaves, it will pass the gene for it to the next progeny as well via organellar DNA. This way the progeny will always have the same leaf color as the female parent.

the corpus luteum secretes estrogens and progesterone. the latter hormone causes changes in the uterus that make it more suitable for implantation of the fertilized ovum and the nourishment of the embryo. if the egg is not fertilized, the corpus luteum becomes inactive after 10–14 days, and menstruation occurs.

i hope this : )

interphase

the period of cell growth when the cell synthesizes new molecules and organelles. the cell is not dividing and it constitutes the majority of the time spent in the cell cycle

prophase

changes occur in the nucleus and cytoplasm. the chromatin condenses to form structures (sister chromatids) visible with a light microscope and the mitotic spindle begins to form, but the nucleus is still in tact

prometaphase

the nuclear envelope fragments and the spindle microtubules attach to the kinetochores of the sister chromatids

metaphase

all the cell's duplicated chromosomes are lined up at an imaginary plane equidistant between the poles of the mitotic spindle

anaphase

begins when sister chromatids separate from each other and ending when a complete set of daughter chromosomes arrives at each of the two poles of the cell

telophase

the daughter nuclei form at the two poles of a cell

cytokinesis

the division of a cytoplasm to form two separate daughter cells. usually occurs during telophase during mitosis. this and mitosis make up to mitotic (m) phase of the cell cycle