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An exogenous contrast agent, in medical imaging for example, is a liquid injected into the patient intravenously that enhances visibility of a pathology, such as a tumor.An exogenous factor is any material that is present and active in an individual organism or living cell but that originated outside that organism, as opposed to an endogenous factor.
External factors such as climate, parent material which forms the soil and topography, control the overall structure of an ecosystem but are not themselves influenced by the ecosystem. Internal factors are controlled, for example, by decomposition , root competition, shading, disturbance, succession, and the types of species present.
External fertilization is a mode of reproduction in which a male organism's sperm fertilizes a female organism's egg outside of the female's body. [1] It is contrasted with internal fertilization , in which sperm are introduced via insemination and then combine with an egg inside the body of a female organism.
For example, research has shown that factors such as access to education, nutrition, and social support can have a significant impact on IQ. Furthermore, research has suggested that certain experiences during early childhood, such as exposure to lead or other environmental toxins, can have a negative impact on IQ.
The concept of Environmental Sensitivity integrates multiple theories on how people respond to negative and positive experiences. These include the frameworks of Diathesis-stress model [4] and Vantage Sensitivity, [5] as well as the three leading theories on more general sensitivity: Differential Susceptibility, [6] [7] Biological Sensitivity to Context, [8] and Sensory processing sensitivity ...
The black walnut secretes a chemical from its roots that harms neighboring plants, an example of competitive antagonism.. In ecology, a biological interaction is the effect that a pair of organisms living together in a community have on each other.
In his 2005 article, Wild stated, "At its most complete, the exposome encompasses life-course environmental exposures (including lifestyle factors), from the prenatal period onwards." The concept was first proposed to draw attention to the need for better and more complete environmental exposure data for causal research, in order to balance the ...
Epigenetic mechanisms. In biology, epigenetics is the study of heritable traits, or a stable change of cell function, that happen without changes to the DNA sequence. [1] The Greek prefix epi-(ἐπι-"over, outside of, around") in epigenetics implies features that are "on top of" or "in addition to" the traditional (DNA sequence based) genetic mechanism of inheritance. [2]