Problem: OPTIONS:
- separates vein
- Back Vein
- skin vein
- umbilical vein
Q: Answer the following question given this paragraph: The placenta develops throughout the embryonic period and during the first several weeks of the fetal period; placentation is complete by weeks 1416. As a fully developed organ, the placenta provides nutrition and excretion, respiration, and endocrine function (Table 28.1 and Figure 28.12). It receives blood from the fetus through the umbilical arteries. Capillaries in the chorionic villi filter fetal wastes out of the blood and return clean, oxygenated blood to the fetus through the umbilical vein. Nutrients and oxygen are transferred from maternal blood surrounding the villi through the capillaries and into the fetal bloodstream. Some substances move across the placenta by simple diffusion. Oxygen, carbon dioxide, and any other lipid-soluble substances take this route. Other substances move across by facilitated diffusion. This includes water-soluble glucose. The fetus has a high demand for amino acids and iron, and those substances are moved across the placenta by active transport. Maternal and fetal blood does not commingle because blood cells cannot move across the placenta. This separation prevents the mother's cytotoxic T cells from reaching and subsequently destroying the fetus, which bears "non-self" antigens. Further, it ensures the fetal red blood cells do not enter the mother's circulation and trigger antibody development (if they carry "non-self" antigens)at least until the final stages of pregnancy or birth. This is the reason that, even in the absence of preventive treatment, an Rh mother doesn't develop antibodies that could cause hemolytic disease in her first Rh+ fetus. Although blood cells are not exchanged, the chorionic villi provide ample surface area for the two-way exchange of substances between maternal and fetal blood. The rate of exchange increases throughout gestation as the villi become thinner and increasingly branched. The placenta is permeable to lipid-soluble fetotoxic substances: alcohol, nicotine, barbiturates, antibiotics, certain pathogens, and many other substances... Q: Capillaries in the chorionic villi filter fetal wastes out of the blood and return clean, oxygenated blood to the fetus through what? A:
Answer: umbilical vein

Problem:OPTIONS:
- mesosphere
- ozone layer
- crust
- stratosphere

Answer the following question given this paragraph: Sure we can! If you've ever flown on a jet airplane, you've been in the stratosphere. Airplanes fly in the stratosphere, because there is less friction. They get better gas mileage and so costs are lower. There is also less turbulence, so passengers are happier. Can you identify the bottom of the stratosphere in the photo? It's where the clouds begin. Remember that all weather is in the troposphere. Q: Planes fly in what layer of the atmosphere because there is less friction and turbulence? A:
****
A: stratosphere

Answer the following question given this paragraph: The expression "it's not the heat, it's the humidity" makes a valid point. We keep cool in hot weather by evaporating sweat from our skin and water from our breathing passages. Because evaporation is inhibited by high humidity, we feel hotter at a given temperature when the humidity is high. Low humidity, on the other hand, can cause discomfort from excessive drying of mucous membranes and can lead to an increased risk of respiratory infections. When we say humidity, we really mean relative humidity. Relative humidity tells us how much water vapor is in the air compared with the maximum possible. At its maximum, denoted as saturation, the relative humidity is 100%, and evaporation is inhibited. The amount of water vapor in the air depends on temperature. For example, relative humidity rises in the evening, as air temperature declines, sometimes reaching the dew point. At the dew point temperature, relative humidity is 100%, and fog may result from the condensation of water droplets if they are small enough to stay in suspension. Conversely, if you wish to dry something (perhaps your hair), it is more effective to blow hot air over it rather than cold air, because, among other things, the increase in temperature increases the energy of the molecules, so the rate of evaporation increases. The amount of water vapor in the air depends on the vapor pressure of water. The liquid and solid phases are continuously giving off vapor because some of the molecules have high enough speeds to enter the gas phase; see Figure 13.33(a). If a lid is placed over the container, as in Figure 13.33(b), evaporation continues, increasing the pressure, until sufficient vapor has built up for condensation to balance evaporation. Then equilibrium has been achieved, and the vapor pressure is equal to the partial pressure of water in the container. Vapor pressure increases with temperature because molecular speeds are higher as temperature increases. Table 13.5 gives representative values of water vapor pressure over a range of temperatures. Q: What happens to the level of relative humidity in the evening as air temperature declines? A:
OPTIONS:
- it goes up and down
- it falls
- nothing
- it rises
it rises

Answer the following question given this paragraph: All elements have an oxidation number of zero in their pure form. Q: In their pure form, all elements have an oxidation number of what? A:
OPTIONS:
- 3
- 2
- 7
- zero

Answer: zero

input: OPTIONS:
- embryo
- fetus
- unfertilized egg
- fertilized egg Now, answer this question: Answer the following question given this paragraph: The Neural Tube To begin, a sperm cell and an egg cell fuse to become a fertilized egg. The fertilized egg cell, or zygote, starts dividing to generate the cells that make up an entire organism. Sixteen days after fertilization, the developing embryo's cells belong to one of three germ layers that give rise to the different tissues in the body. The endoderm, or inner tissue, is responsible for generating the lining tissues of various spaces within the body, such as the mucosae of the digestive and respiratory systems. The mesoderm, or middle tissue, gives rise to most of the muscle and connective tissues. Finally the ectoderm, or outer tissue, develops into the integumentary system (the skin) and the nervous system. It is probably not difficult to see that the outer tissue of the embryo becomes the outer covering of the body. But how is it responsible for the nervous system? As the embryo develops, a portion of the ectoderm differentiates into a specialized region of neuroectoderm, which is the precursor for the tissue of the nervous system. Molecular signals induce cells in this region to differentiate into the neuroepithelium, forming a neural plate. The cells then begin to change shape, causing the tissue to buckle and fold inward (Figure 13.2). A neural groove forms, visible as a line along the dorsal surface of the embryo. The ridge-like edge on either side of the neural groove is referred as the neural fold. As the neural folds come together and converge, the underlying structure forms into a tube just beneath the ectoderm called the neural tube. Cells from the neural folds then separate from the ectoderm to form a cluster of cells referred to as the neural crest, which runs lateral to the neural tube. The neural crest migrates away from the nascent, or embryonic, central nervous system (CNS) that will form along the neural groove and develops into several parts of the peripheral nervous system (PNS), including the enteric nervous tissue. Many tissues that are not part of the nervous system also arise... Q: A sperm cell and an egg cell fuse to become what? A:
A:
output:
fertilized egg