Answer:
Option C. A hypothesis is considered false until proven true, is the correct answer.
Explanation:
Hypothesis is a statement that may be true or false. In hypothesis, a scientist make a statement which can be both true or false. For example, when a scientist analyze malaria disease, he make a hypothesis that malaria disease is caused due to bad air but when he perform an experiment, he concluded that the malaria is caused due to mosquitoes.
Answer:
Tropical- rain forests are considered to be the lungs of the Earth due to their role in the carbon-oxygen cycle. The rain forests take in carbon dioxide and release oxygen into the Earth hence, providing the Earth with an abundance of oxygen. The working of these tropical rain forests is just like the working of our lungs, lungs remove carbon dioxide from the body and supply oxygen. Tropical rain forests carbon dioxide for the Earth and supplies it with oxygen.
The cytoskeleton of a cell allows the cell to be flexible. Our human skeletons allow <em>us </em>to be flexible.
Answer:
Extrinsic regulatory mechanisms are external and depend on the firing of some factor outside the population itself. Among them are interspecific competition, food and space restrictions, very strong climatic variations, weathering and inharmonious relationships with other populations (parasitism and predatism).
Good examples of interspecific competition appear when rabbits, caves, rats compete for the same plant, or different fish and birds, such as the heron, vie for the same species of smaller fish. This is because these different species keep their populations in the same ecological niche. Competition is often so strong that some species eventually, as one example of an extrinsic homeostatic mechanism overriding an intrinsic homeostatic process is their disappearance or migration to other regions.
In this competition, the presence of adaptations among individuals in the population that promote better food search, speed, vision, and others can make the difference between elimination and survival.
The correct answer is option d, that is, neurotransmitters.
A neurotransmitter refers to a chemical component, which is discharged at the terminal of a nerve fiber by the introduction of a nerve impulse, and by diffusing across the junction or synapse. It helps in the transfer of the impulse to another muscle fiber, nerve fiber, or some other composition. Acetylcholine is a kind of neurotransmitter, that is, used by neurons in the CNS and the PNS in the control of activities ranging from heart rate and muscle contraction to digestion and memory.
