Q: Which of the following equations correctly represents the chromosome number in a human zygote?

$$46 = 23_{\text{maternal}} + 23_{\text{paternal}}$$

Question 1

During which period is the basic organization of the human body plan established?

Accepted Answer

Embryonic period

Question 2

Which structure is responsible for preventing polyspermy after fertilization?

Accepted Answer

Zona pellucida

Question 3

What is the correct sequence of early embryonic development from fertilization to implantation?

Accepted Answer

Zygote → Morula → Blastocyst → Implantation

Question 4

Which embryonic tissue layer gives rise to the nervous system?

Accepted Answer

Ectoderm

Question 5

A patient presents with an ectopic pregnancy. Which of the following best describes this condition?

Accepted Answer

The embryo implants outside the uterus

Question 6

Which of the following is a characteristic shared by all epithelial tissues?

Accepted Answer

Cells are tightly packed with little extracellular space

Question 7

The amniotic cavity is formed from which bilaminar tissue?

Accepted Answer

Epiblast

Question 8

Which of the following best describes holoblastic cleavage?

Accepted Answer

Cleavage occurs throughout the entire zygote, producing equally sized cells

Question 9

Which layer of the trilaminar embryo is located on the dorsal surface and gives rise to the skin and nervous system?

Accepted Answer

Ectoderm

Question 10

Which of the following is NOT a function of the trophoblast during early development?

Accepted Answer

Forming the inner cell mass

Question 11

Which of the following equations correctly represents the chromosome number in a human zygote?

Accepted Answer

$$46 = 23_{	ext{maternal}} + 23_{	ext{paternal}}$$

Question 12

Which embryonic structure is responsible for nutrient transfer before the placenta is fully developed?

Accepted Answer

Yolk sac

Question 13

A mutation prevents the formation of the primitive streak during gastrulation. Which process would be directly affected?

Accepted Answer

Formation of the trilaminar embryo

Question 14

Which of the following is a feature of all connective tissues?

Accepted Answer

Presence of an extracellular matrix

Question 15

Which adult tissue is derived from the mesoderm?

Accepted Answer

Muscle tissue

Question 16

If the blastocyst fails to shed the zona pellucida, which process is most likely to be impaired?

Accepted Answer

Implantation into the uterine wall

Question 17

Which of the following best explains why cells in the morula are smaller than the original zygote?

Accepted Answer

Cleavage increases cell number without increasing total volume

Question 18

Which of the following is the correct order of tissue layer formation during embryogenesis?

Accepted Answer

Epiblast and hypoblast → Ectoderm, mesoderm, endoderm

Question 19

A researcher observes a developing embryo with a well-formed amniotic cavity and yolk sac, but no primitive streak. Which stage is the embryo most likely in?

Accepted Answer

Bilaminar embryo

Human Body Plan Development: Embryology and Tissue Formation

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