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Fertilization & Twinning: A Review

Total questions: 18

Worksheet time: 9mins

Name
Class
Date
1.

Identical twins are formed by the fusion of ____ sperm and ___ egg(s).

a)

one; one

b)

one; two

c)

two; one

d)

two; two

2.

The single-celled organism that that results from the fusion of a sperm and an egg is called a ________.

a)

ovum

b)

zygote

c)

fertilyte

d)

placenta

3.

Identical twins, triplets, or quadruplets are all ________, meaning they resulted from a single sperm and egg that formed a zygote....that then SPLIT!

a)

dizygotic

b)

trizygotic

c)

monozygotic

d)

quadrizygotic

4.

Fraternal twins are also known as _______ twins.

a)

identical

b)

non-identical

5.

The twins in this image share 100% of their DNA. These are ___________ twins.

a)

identical

b)

fraternal

6.

The twins in this image are ________.

a)

identical

b)

fraternal.

7.

All identical twins are the same biological sex (two females or two males).

a)

True

b)

False

8.

Fraternal twins are always the same biological sex (two females or two males).

a)

True

b)

False

9.

The structure labeled A in this image is the _________.

a)

chorion

b)

amnion

c)

placenta

d)

umbilical cord

10.

The structure labeled B in this image is the _________.

a)

chorion

b)

amnion

c)

placenta

d)

umbilical cord

11.

The twins in this image are ________________.

a)

monochorionic monoamniotic ("Mo/Mo")

b)

monochorionic diamniotic ("Mo/Di")

c)

dichorionic diamniotic ("Di/Di")

12.

The twins in this image are ________________.

a)

monochorionic monoamniotic ("Mo/Mo")

b)

monochorionic diamniotic ("Mo/Di")

c)

dichorionic diamniotic ("Di/Di")

13.

The twins in this image are ________________.

a)

monochorionic monoamniotic ("Mo/Mo")

b)

monochorionic diamniotic ("Mo/Di")

c)

dichorionic diamniotic ("Di/Di")

14.

Which is more common, identical or non-identical (fraternal) twins?

a)

Identical

b)

Fraternal

15.

Amniotic fluid has the function of _____________.

a)

providing fresh oxygen and nutrients to the growing baby

b)

cushioning the baby to prevent injury

c)

connecting the baby to the placenta

d)

all of the above

16.

What are the sex chromosomes of a genetic male?

a)

XX

b)

XY

c)

YY

17.

What are the sex chromosomes of a genetic female?

a)

XX

b)

XY

c)

YY

18.

Fraternal twins share _____ of their DNA.

a)

0%

b)

50%

c)

100%