Question 1

Marisa is at a point in her pregnancy when the zygote is moving down to her uterus,and the placenta and umbilical cord are beginning to form.Which period of prenatal development is Marisa currently experiencing?

Accepted Answer

The germinal period is the first stage of prenatal development, lasting from conception to about two weeks, during which the zygote moves to the uterus and the placenta and umbilical cord begin to form.

Question 2

Abby and Brittany Hensel _______.

Accepted Answer

Abby and Brittany Hensel are conjoined twins who share one body from the waist down, including some internal organs, but they have separate hearts and stomachs.

Question 3

The germinal period _______.

Accepted Answer

The germinal period is the first stage of prenatal development, which occurs during the first two weeks after fertilization. During this period, the fertilized egg develops into a blastocyst, and eventually implants in the uterine wall.

Question 4

_______ develop when two eggs each get fertilized by two different sperm,resulting in two zygotes in the uterus at the same time.

Accepted Answer

Dizygotic twins, also known as fraternal twins, develop when two separate eggs get fertilized by two different sperm. This results in two zygotes in the uterus at the same time, making them genetically distinct individuals. Monozygotic twins, on the other hand, develop from a single fertilized egg that splits into two embryos. Wombmates is not a scientific term used to describe twins.

Question 5

Which of the following describes the embryonic period?

Accepted Answer

The embryonic period is the period during which the major organs and structures of the organism first develop, typically occurring from week 2 to week 8 of gestation. During this time, the fertilized egg (now called a blastocyst) implants in the uterus and the three germ layers form, which then differentiate into organs and structures.

Question 6

Times when certain internal and external influences have a major impact on development are called _______.

Accepted Answer

Critical periods refer to specific times during development when certain experiences and influences have a particularly strong impact on later development. During these periods, the developing brain and body are particularly responsive to environmental stimuli, and the absence or presence of certain experiences can have lifelong implications. Examples of critical periods include the first 3 years of life (language development), puberty (sexual maturation), and adolescence (social and emotional development).

Question 7

Which of the following terms is used to describe any substance,such as a drug,chemical,or virus that can bring about a birth defect?

Accepted Answer

A teratogen is any substance or agent that can cause birth defects or malformations in a developing embryo or fetus. Examples of teratogens include drugs, chemicals, and viruses. A critical period is a specific time during fetal development when a particular organ or structure is most vulnerable to damage by teratogens. Carcinogens are substances that can cause cancer, and biohazards are substances or organisms that pose a threat to human health or the environment.

Question 8

The union of the ovum and sperm is called _______.

Accepted Answer

Fertilization is the process by which the genetic material from the sperm and the ovum combine to form a new cell, called a zygote. This is the first stage in the development of a new individual.

Question 9

Which of the following describes the way in which monozygotic twins occur?

Accepted Answer

Monozygotic or identical twins occur when a single fertilized egg (zygote) splits into two separate embryos. This happens very early in development, usually within the first week after fertilization. As a result, the twins have the same genetic material and are essentially clones of each other.

Question 10

Tameeka is at a point in her pregnancy during which the major organs and structures of her baby are first developing.Which period of prenatal development is Tameeka currently experiencing?

Accepted Answer

The embryonic period is the stage of prenatal development from approximately 2-8 weeks after conception. During this time, the major organs and structures of the baby begin to form.

Question 11

The specialized organ that provides nourishment and filters away waste products from the developing baby is called the _______.

Accepted Answer

The placenta is a specialized organ that develops in the uterus during pregnancy and provides nourishment, oxygen, and removes waste products from the developing baby. The uterus is the muscular organ where the baby grows and develops, but it does not directly provide nourishment or filter waste products. The umbilical cord connects the developing baby to the placenta and serves as a pathway for blood flow and exchange of nutrients, but it is not an organ itself. The embryo is the early stage of development before the fetus stage, and it is not a specialized organ that provides nourishment or filters waste products.

Question 12

Greta's child has facial deformities,a smaller than normal head,heart defects,mental retardation,learning difficulties,and delayed growth.If these defects can be traced to a teratogen used by Greta when she was pregnant,which was she most likely abusing?

Accepted Answer

The combination of physical and cognitive impairments described in Greta's child are consistent with fetal alcohol syndrome, a condition caused by maternal consumption of alcohol during pregnancy. None of the other options listed would typically cause all of these symptoms.

Question 13

Ashley and Mary-Kate are twins who are genetically identical.What type of twins are they?

Accepted Answer

Ashley and Mary-Kate are genetically identical, indicating that they are monozygotic twins, which means they developed from a single fertilized egg that split into two embryos.

Question 14

Monozygotic twins _______.

Accepted Answer

Monozygotic twins, also known as identical twins, are formed when a fertilized egg splits into two embryos. As a result, the twins are genetically identical to each other because they came from the same fertilized egg.

Question 15

Brittany and Abby Hensel are _______.

Accepted Answer

Brittany and Abby Hensel are conjoined twins, meaning they are physically connected to each other. Nonidentical, dizygotic, and fraternal twins all refer to twins that are formed from two separate embryos.

Question 16

Mary and Juan are twins who developed from two separate fertilized ova that were fertilized by two different sperm.What type of twins are they?

Accepted Answer

Mary and Juan are dizygotic (fraternal) twins, as they developed from two separate fertilized ova (eggs) and two different sperm. Monozygotic (identical) twins develop from a single fertilized ovum that splits into two embryos, while maternal twins is not a correct term for describing the type of twins. "Wombmates" is not a recognized scientific term for describing twins.

Question 17

Conjoined twins are _______.

Accepted Answer

Conjoined twins are always monozygotic (identical) twins who have failed to separate completely during embryonic development.

Question 18

Fraternal twins are _______ similar genetically than are other brothers and sisters.

Accepted Answer

Fraternal twins are genetically similar to each other as any other siblings because they come from two separate eggs fertilized by two separate sperm, sharing about 50% of their DNA.

Question 19

Emily and her husband are thrilled as they peer into Emily's uterus by means of an ultrasound.The physician reports that the pregnancy appears normal,and that their baby's fingers,toes,heart,and circulatory system are developing as expected.The couple learns that the baby is only an inch long.Given this information,the current stage of prenatal development is the _______.

Accepted Answer

The embryonic period occurs from the third to the eighth week of pregnancy, during which major organs and structures begin to develop, including fingers, toes, heart, and circulatory system. The baby being only an inch long aligns with this stage.

Question 20

In the process of fertilization,the _______ and _______ unite,resulting in a single cell.

Accepted Answer

Fertilization is the process in which the sperm and ovum (egg cell) unite to form a single cell called a zygote. Therefore, the best choice is A) sperm and ovum.

Quiz 8: Development Across the Life Span