Answer:
b. a greater chance to survive if environmental conditions suddenly change
Explanation:
When a species of organism has a wide variety of characteristics, it means that that species has many opportunities to adapt and survive different environmental conditions, even if those conditions change suddenly. This is because, this variety of characteristics allows this species to adopt the most variable survival strategies.
Gradual changes in the frequency of diseases over long periods are known as SECULAR TIME TRENDS. For example, the rate of mortality in USA due to coronary heart diseases over a period of time. Onset of puberty in girls is also a secular time trend.
Secular time trend is also referred as Secular Variation and Secular Drift.
The answer is <span>insect and pest populations decreased.
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DDT (dichlorodiphenyltrichloroethane) was used as an insecticide which is a substance used to kill insects. That resulted in decrease in insect and pest populations. It is a persistent and non-degradable insecticide, but as well organic pollutant readily accumulated to soils and consequently affects organisms.
