Every passing day we are exposed to a cocktail of chemicals through medicines, cosmetics, pesticides, aerosols, gaseous emissions, pollens, etc. Many of these affect our health; some are allergens, while others could be carcinogens or cause fatal diseases. Although some products are tested to ascertain their safety for human use, the process is tedious, time-consuming and involve testing on animals.
Researchers found that urban female sparrows invest more time and energy into parental care than their rural counterparts, yet have significantly lower reproductive success.