Answer:
Virus transmission is affected by a number of factors, including environmental determinants, host behavior, host defense mechanisms, and virus infectivity.
Explanation:
Answer:
Gastrulation.
Explanation:
The embryonic development occurs through the different developmental stages like cleavage, morula, blastula and so on. The formation of the germ layers occur in the gastrulation period.
The primitive streak is the structure that develops during the early stages of the gastrulation. As the embryo becomes asymmetric., the cells moves from their initial position and leads to the formation of primitive streak in the gastrulation phase.
Thus, the correct answer is option (C).
Answer:
The correct answer to the question: The pineal body secretes which hormone that maintains the body´s internal clock, the 24-hour wake-sleep cycle, and regulates the onset and duration of sleep?, would be, C: Melatonin.
Explanation:
The process of sleep and wakefulness, also called the circadian cycle, its a pretty complex system that is controlled by several parts of the brain, but most importantly, structures of the diencephalon (vital is the hypothalamus), the pineal gland, and the stem of the brain. All these structures, and some others, respond to changes both in light perception by the eyes and other senses, heat, and homeostatic balances. These factor play a vital role in telling the human body that it is time for sleep, or to awaken. The pineal gland, as part of this melody, is essential, as it secretes the hormone, melatonin, in response to light changes. Melatonin will balance out the process of sleep, when it is secreted in high quantities by the pineal gland, and wakefulness, when it is no longer secreted in response to the presence of light. This is what is called the circadian cycle.
Answer:
Toxocara canis
Explanation:
Predator prey route is the transmission method used by different protozoa. They enter the body of the prey when they eat an infected prey. They are infused in the blood of the predator and then resides there forming an infection. They overcome transmission barriers and enters the body of host.
