Non-disjunction involving the x-chromosome may occur during oogenesis and produce two kinds of eggs. if normal sperm fertilize these two types, which of the following pairs of genotypes are possible?

a. xx and xy
b. xxy and xo
c. xyy and xo
d. xyy and yo

The correct answer will be option-B

Explanation:

Non-disjunction is the process of the failure of the separation of the homologous chromosomes during cell division which could be observed during the meiosis I, meiosis II or mitosis.

If Non-disjunction takes place during the oogenesis then the resultant cells will be formed with XX and O gametes.

When a normal male sperm with XY fertilizes the cells then they will form four combinations:

1. XX  + X = XXX

2. XX + Y  = XXY

3. O + X = XO

4. O + Y = YO

Thus, in the given question option-B is the correct answer.

primary succession occurs in essentially lifeless areas regions in which the soil is incapable of sustaining life as a result of such factors as lava flows, newly formed sand dunes, or rocks left from a retreating glacier. secondary succession occurs

i'm guessing this is from edg enuity so the answers would be, from top to bottom,

theodor schwann

matthias schleiden

robert hooke

rudolph virchow

anton van leeuwenhoek