Is Starkly a Adverb?

The adverb starkly is good for talking about things that are visually severe or harsh, like the silhouette of a crow that stands starkly against the gray sky.

Is Furiously an adjective or adverb?

furiously adverb (ANGRILY)

Is yelled a adverb?

We do not currently know of any adverbs for yelled. Using available adjectives, one could potentially construct nonstandard adverbs such as yellly, yellerly, yellingly, yelledly, yellochingly or yellochedly.