Which statement regarding Bacillus anthracis is incorrect?

Bacillus anthracis is a Gram-positive bacterium recognized as one of the main causes of anthrax. This bacterium is known for its ability to form spores, which contribute to its resilience and survival in various environmental conditions, making it a well-studied pathogen in microbiology.

The statement regarding its growth primarily under anaerobic conditions is incorrect. Bacillus anthracis actually grows well in aerobic environments and is classified as a facultative anaerobe, meaning it can grow in both the presence and absence of oxygen, but it does not primarily require anaerobic conditions. This distinction is significant as it relates to the bacterium's natural habitat and its pathogenic processes, which are typically associated with aerobic conditions in the host environment.

In contrast, the other statements accurately describe characteristics of Bacillus anthracis: it is indeed Gram-positive, capable of forming durable spores, and is the causative agent of anthrax, each of which is critical for understanding its biology and impact on health.