The correct answer is:
There is no ASSOCIATION between fluoride exposure and increased cancer risk in humans.
Answer choice A.
C : the migration of people from the county to the city.
Answer:
Heterotrophs are the organisms which cannot prepare their food on their own like autotrophs instead are dependent on other mode to obtain the organic substances from the environment. This method is common in animal and fungi groups.
Although both fungi and animals are heterotrophs their mode of heterotrophic is different as fungi obtain organic substance b secreting many digestive enzymes which digests the complex biomolecules and the fungi obtain the organic substances whereas the animals swallow or ingest the material and then digests it.
The answer would be C as it can be directly tested experimentally and observed that bacteria adapted to become drug resistant and the natural selection of drug resistant bacteria to survive and continue proliferating, thus being direct evidence of evolution
