The sentence that serves as the hook in this introductory paragraph is B. For the first time in decades, Baby Boomers have been outnumbered by another. In essay writing, 'hook' is the part of essay that grabs readers' attention. In other words, it is the most significant sentence of the whole introduction of your writing. The 'hook' is usually put in the first or the second sentence of the introduction. This sentence contain information that creates sort of suspense, and its catchy structure is defined as 'hook'.
Salamanders can regrow entire limbs and regenerate parts of major organs, an ability that relies on their immune systems, research now shows. ... They then wiped out some or all of the macrophage cells to determine whether these cells were essential for regrowing the limbs.
