Q.Yucca plant
I was moving my Yucca plant. While moving it, I dropped the pot and decapitated the top part of the plant. Can the leafy decapitated part be placed in water and grow roots? Will the stem produce new growth?

I'm sorry your plant got accidentally beheaded! YES, the top part can become a new plant with a little care. This article will walk you through how: https://www.gardeningknowhow.com/ornamental/foliage/yucca/propagation-of-yucca-plant.htm
And even more good news: YES, the trunk can be re-rooted. This article will walk you through how: https://www.gardeningknowhow.com/ornamental/foliage/yucca/yucca-plants-care-and-pruning-tips-for-pruning-a-yucca.htm