: difficult in a way that is usually interesting or enjoyable. Thesaurus: All synonyms and antonyms for challenging Nglish: Translation of challenging for Spanish speakers Britannica English: Translation of challenging for Arabic speakers.
To illustrate the tremendous indirect impact of emerging zoonotic diseases on public health policy and structures and on public perception of health risks, the authors provide a number of examples, including that of the Ebola virus, avian influenza, monkeypox and bovine spongiform encephalopathy.
The two-hour program charts the fetal development of three mammals--the dolphin, dog and elephant--with special imagery rarely seen outside a zoologist's office. Scientists used advanced ultrasound technology, called 4D (for four dimensions), to capture three-dimensional images of the animals inside the womb.t's just a matter of time before each species develops its defining characteristics. Dolphins, for example, develop tiny leg-like limb buds during their first month in the womb, but the buds vanish within two weeks, and the animals swim in amniotic fluid for the next 11 months of gestation.