Question 1

Which of the following best describes the process that determines the sex of an offspring in humans?

Accepted Answer

The type of sperm (X or Y chromosome) that fertilizes the oocyte

Question 2

When an oocyte is ovulated, which of the following best describes its state?

Accepted Answer

It is a secondary oocyte arrested in metaphase II

Question 3

Amphimixis refers to which of the following events during fertilization?

Accepted Answer

The mixing of maternal and paternal chromosomes to form a zygote

Question 4

Which of the following correctly matches the major changes that occur in each trimester of human pregnancy?

Accepted Answer

First trimester: organogenesis; Second trimester: growth and development; Third trimester: preparation for birth

Question 5

How does a zygote become a morula?

Accepted Answer

By undergoing repeated mitotic divisions without significant growth

Question 6

Which process transforms a morula into a blastocyst?

Accepted Answer

Formation of the trophoblast and development of a fluid-filled cavity

Question 7

Which of the following correctly describes the layers of a blastocyst?

Accepted Answer

Trophoblast (outer layer) and inner cell mass (embryoblast)

Question 8

Implantation of the blastocyst occurs through which mechanism?

Accepted Answer

The blastocyst burrows into the endometrium using enzymes released by the trophoblast

Question 9

Which of the following best describes the formation of the blastodisc?

Accepted Answer

The inner cell mass flattens and forms a two-layered disc

Question 10

The neural tube is the precursor to which major body system?

Accepted Answer

Nervous system

Question 11

Which of the following correctly matches each germ layer with the structures it produces?

Accepted Answer

Ectoderm: skin and nervous system; Mesoderm: muscles and bones; Endoderm: digestive and respiratory tracts

Question 12

Which of the following lists the four extraembryonic membranes and their primary functions?

Accepted Answer

Amnion (protects embryo), chorion (forms placenta), yolk sac (early blood cell formation), allantois (waste storage and gas exchange)

Question 13

Which statement best describes the difference between monozygotic and dizygotic twins?

Accepted Answer

Monozygotic twins are genetically identical; dizygotic twins are genetically distinct

Question 14

Which of the following changes occurs in the maternal respiratory system during gestation?

Accepted Answer

Increased tidal volume and increased oxygen demand

Question 15

After the fetus is born, what happens to the placenta?

Accepted Answer

It is expelled from the uterus as the afterbirth

Question 16

Which of the following best describes the three stages of labor?

Accepted Answer

Dilation, expulsion, placental

Question 17

During the neonatal period, which of the following changes occurs in the newborn?

Accepted Answer

Closure of the foramen ovale and ductus arteriosus in the heart

Question 18

Which of the following correctly defines the terms gene, allele, and locus?

Accepted Answer

Gene: a segment of DNA coding for a trait; Allele: a variant form of a gene; Locus: the physical location of a gene on a chromosome

Question 19

In genetics, which of the following best describes a monohybrid cross?

Accepted Answer

A cross involving one pair of contrasting traits, such as $$AA 	imes aa$$

Question 20

Which of the following is an example of a sex-linked cross?

Accepted Answer

A cross involving the $$X$$ and $$Y$$ chromosomes, such as $$X^N X^n 	imes X^N Y$$

Human Development and Heredity: Study Guide

Study Guide - Practice Questions