Final answer:
Oomycetes, once thought to be closely related to fungi due to their similarities, are actually more closely related to certain algae within the protists, not fungi, plants, animals, or bacteria.
Step-by-step explanation:
The question 'Which taxa share a recent common ancestor with oomycetes?' refers to the relationships among different groups of organisms and their evolutionary history. Oomycetes, also known as water molds, have similarities to fungi, but they are distinct in several important ways such as having cell walls made of cellulose instead of chitin, and being generally diploid instead of the typically haploid dominance in the fungi life cycle.
Oomycetes were once classified with fungi due to their similar lifestyles, but molecular studies have since placed them closer to the kingdoms of algae within the protists. Therefore, although oomycetes share some characteristics with fungi, they are not as closely related genetically or evolutionarily to fungi, plants, animals, or bacteria.