1.
Sperm goes into an egg and fertilizes it. Chromosomes with 30,000 genes combine and determine the physical characteristics of what will soon be the baby.
Correct Answer
B. Fertilization
Explanation
Fertilization is the process in which a sperm cell enters an egg cell and combines their genetic material, including the chromosomes with approximately 30,000 genes. This combination of genetic material will determine the physical characteristics of the developing baby. Therefore, fertilization is the correct answer that best fits the given information.
2.
The first division after fertilization happens at what stage?
Correct Answer
C. 2 cell stage
Explanation
After fertilization, the zygote undergoes its first division at the 2 cell stage. This means that the zygote divides into two cells, which are the first cells of the developing embryo. This division is crucial for the subsequent development of the embryo and is an important milestone in early embryogenesis.
3.
When 50% of pregnancies fail-only a 50% chance of the baby surviving at the point of __________.
Correct Answer
C. Day 23
Explanation
Day 23 is the point at which the baby has implanted in the uterus and has started to develop. At this stage, there is a 50% chance of the baby surviving because it has successfully implanted and is progressing in its development. The other options, such as gastrulation or day 21, do not specifically indicate the point at which the baby has implanted and therefore do not align with the given information.
4.
When the cells in the morula change positions and create a fluid-filled cavity it is called _____________.
Correct Answer
B. Blastocyst
Explanation
When the cells in the morula change positions and create a fluid-filled cavity, it is called a blastocyst. This is an important stage in embryonic development, where the inner cell mass forms the embryo and the outer cell mass forms the placenta. The blastocyst is responsible for implanting into the uterine wall and initiating pregnancy.
5.
At what stage does the human baby heart start beating?
Correct Answer
A. Day 21
Explanation
The human baby's heart starts beating on day 21. This is the stage when the heart begins to form and starts its rhythmic contractions. This early development of the heart is crucial for the baby's growth and survival.
6.
Both of the 2 cells divide creating four cells and eventually growing into the morula at stage _________.
Correct Answer
A. 4 cell stage
Explanation
At the 4 cell stage, both of the 2 cells divide, resulting in the formation of four cells. This stage is an early stage of embryonic development, known as the morula stage. The morula is a solid ball of cells that will continue to divide and develop into a blastocyst, which later implants into the uterine wall. Therefore, the correct answer is the 4 cell stage.
7.
When the blastocyst is implanted into the wall of the uterus and starts developing and sends out hormones into the bloodstream, this stage is referred as ___________.
Correct Answer
C. Implantation
Explanation
Implantation is the correct answer because it refers to the stage when the blastocyst, a hollow ball of cells, attaches itself to the uterine wall and begins to develop. During this process, the blastocyst releases hormones into the bloodstream, which is a key characteristic of implantation. Fertilization is the process of the sperm and egg joining, while the morula is an earlier stage of embryonic development before the blastocyst forms.
8.
The morphology of the embryo forms 3 different layers: the ectoderm, mesoderm, and _____________.
Correct Answer
C. Endoderm
Explanation
The morphology of the embryo forms 3 different layers: the ectoderm, mesoderm, and endoderm. The ectoderm gives rise to the nervous system, skin, and hair. The mesoderm forms the muscles, bones, and circulatory system. The endoderm develops into the lining of the digestive tract, respiratory system, and various internal organs such as the liver and pancreas. These three layers are essential for the proper development and differentiation of the embryo into a fully formed organism.
9.
What is the placenta?
Correct Answer
B. The organ that provides nutrients and gets rid of waste
Explanation
The placenta is an organ that develops during pregnancy and is attached to the uterine wall. Its main function is to provide nutrients and oxygen to the developing fetus, as well as remove waste products such as carbon dioxide. It acts as a barrier between the mother's blood supply and the baby's, allowing for the exchange of substances while keeping them separate. Therefore, the correct answer is "the organ that provides nutrients and gets rid of waste."
10.
In which week does the baby start developing its ears and toes?
Correct Answer
C. Week 7
Explanation
During week 7 of pregnancy, the baby starts developing its ears and toes. This is a crucial stage of fetal development, as the ears begin to form and the toes start to take shape. It is during this time that the baby's body is rapidly growing and developing, and the organs and limbs are starting to form. Therefore, week 7 is the correct answer as it marks the beginning of ear and toe development in the baby.
11.
What does the pancreas do for the baby?
Correct Answer
B. Producing insulin
Explanation
The pancreas produces insulin, which is a hormone that helps regulate blood sugar levels. This is important for the baby's overall health and development. Insulin allows the body to use glucose from the bloodstream as a source of energy. Without insulin, blood sugar levels can become imbalanced, leading to potential health complications. Therefore, the pancreas plays a crucial role in producing insulin for the baby's well-being.
12.
The first trimester spans from conception to _________.
Correct Answer
A. 12 weeks
Explanation
The first trimester of pregnancy typically lasts for 12 weeks. During this time, the fertilized egg implants itself into the uterus and begins to develop into an embryo. By the end of the first trimester, the embryo has grown into a fetus, with all major organs and body systems formed. This is an important milestone in pregnancy as the risk of miscarriage significantly decreases after the first trimester.
13.
The fingernails and toenails of the baby begin developing between ________.
Correct Answer
D. Week 13 to 18
Explanation
Between weeks 13 to 18, the baby's fingernails and toenails begin developing. This is a crucial period in fetal development when various organs and body parts start to form. The development of the nails is part of the overall growth and maturation process during this stage of pregnancy.
14.
The reproductive organs and genitalia of the baby get developed by week _________.
Correct Answer
D. Weeks 13 to 16
Explanation
During weeks 13 to 16 of pregnancy, the reproductive organs and genitalia of the baby start to develop. This is a crucial period in fetal development as the baby's sex organs begin to form and differentiate. By this stage, the baby's external genitalia can be identified through ultrasound. The development of these organs during this time is an important milestone in the baby's growth and development.
15.
How much does a newborn baby weigh?
Correct Answer
B. 7 pounds
Explanation
A newborn baby typically weighs around 7 pounds. This is considered to be a healthy weight range for a newborn. Babies can vary in weight, but 7 pounds is a common average.