The necessary genotype for a female zygote is XX.

The mother will share this XX genotype (since she is also female) and will contribute one X-chromosome. The father, however, will be male and have the genotype XY. This means he has a 50% chance of passing on an X-chromosome and a 50% chance of passing on a Y-chromosome. If the zygote inherits a Y-chromosome from the father's sperm, then the offspring will be male. If the zygote inherits an X-chromosome from the father's sperm, then the resulting genotype will be XX and the offspring will be female.

Totipotent cells have the ability to propogate and differentiate into any cell types, including the trophoblast. They are different from stem cells, which could be considered multipotent (able to differentiate into multiple tissue types) or pleuripotent (able to differentiate into any major tissue type, but cannot create trophoblast). The only truly totipotent cells are the first two blastomeres.

Most cells contain a complete genome, but not all genes are activated in each cell. Activation of particular genes produces appropriate protein function.

The endoderm develops into a number of internal organs, including the lung, which are vital for breathing.

The kidneys (urine production), muscles (movement), and blood vessels (blood circulation) develop from the mesoderm. The brain (thought) develops from the ectoderm.

This question is targeting your knowledge of the circulatory system. Since the medication has a short half-life, it is necessary that it be carried by the patient's blood stream to the tumor as quickly as possible. Blood travels through the right side of the heart, to the lungs, through the left side of the heart, then to the body. Therefore, inhalation of a chemical would require the least amount of traveling (Lungs, Left Atrium, Left Ventricle, Body). Each other method of administration, including IV, would require more time to travel to the brain. For example, for the IV answer choice, the pathway would be Vein, Right Atrium, Right Ventricle, Lungs, Left Atrium, Left Ventricle, Body.

Like many biological functions, thermoregulation is controlled by a negative feedback system. This is because the response is the opposite of the input: a hot environment triggers cooling, while a cool environment triggers heating. A positive feedback system would intensify a response in the same direction as the input. If a positive feedback mechanisms were true of regulating body temperature, cold weather would trigger sweating and dilation of blood vessels. The result would be that you would get even more cold, which would not be good for maintaining homeostasis. Hormones do help regulate many body functions, but they are not the best description of how body temperature is controlled.

In its home environment, the fresh water fish will be in equilibrium with its surroundings. As such, it will essentially be isotonic with a fresh water solution. This represents a relatively low solute concentration in the fish's body.

When we transfer this fish to a medium that is more densely concentrated with solute molecules, the fresh-water fish will be hypotonic in relation to the external medium. The salt in the surrounding water will cause the external environment to be more concentrated than the body of the fish. As a result, the fish will quickly become dehydrated as water exits its body.

Hypertonic and hyperosmotic are synonyms, which both refer to greater concentrations than the surroundings (opposite the scenario described).

Answering this question depends on your knowledge of concentration gradients and solution chemistry. Even though the sodium hydroxide and glucose solutions are equimolar, sodium hydroxide is an electrolyte, meaning it dissociates when in solution. The solute content of the sodium hydroxide solution is actually twice that of the glucose solution due to the presence of ions. This means that the sodium hydroxide solution will actually be hypertonic with respect to the glucose solution.

Only water can cross the semi-permeable membrane; the ions will be trapped in their respective chambers. Water from the glucose solution will diffuse down its concentration gradient into the sodium hydroxide solution. After the system equilibrates, the water level in the sodium hydroxide solution will be higher.

The four incorrect answers are simply the foundation of the Cell Theory, and you should know them.  While all cells have a membrane enclosing the whole cell, not all have a membrane-bound nucleus.  Prokaryotes have a nucloid that contains most of the genetic material, but it is not bound.

Not all cells need to undergo oxidative phosphorylation to produce energy; they can also use anaerobic respiration or other methods of energy production.

The cell theory states that all living things are made of one of more cells, and that a cell is the basic functional unit of life. The theory claims that any cell must have originated from a pre-existing cell, detailing the concept of cellular reproduction. These three claims form the broad arc od concepts of the cell theory. Additional sub-claims to the theory dictate that cells contain DNA and require energy (nutrients).