Learn Croatian: Bi li ijedna deva pojela ovaj žućkasti grm? - Would any camel eat this yellowish bush?

ijedna specifically means "even a single one" or "any at all". It is formed from i- plus jedna (one) and declines exactly like jedan. While neka deva would just mean "some camel", ijedna deva heavily stresses the doubt that even one single camel would eat the bush.

Why do ovaj and žućkasti look like they are in the nominative case even though they are the direct object?

The phrase ovaj žućkasti grm is actually in the accusative case. Because grm (bush) is a masculine inanimate noun, its accusative form is identical to its nominative form. The adjectives and demonstrative pronouns modifying it must follow that same inanimate rule, keeping their nominative-like endings.

What does the suffix in žućkasti do to the root word?

The suffix -kast translates to "-ish" in English, softening or weakening the intensity of an adjective. It is very commonly used with colors. Here, the root žut (yellow) undergoes a slight consonant change and becomes žućkast (yellowish).

Why does the sentence begin with Bi li instead of Da li bi?