Sentence:  An aqueous suspension of the <WSD>spores</WSD> of B. subtilis , var. niger , generally known as Bacillus globigii , was aerosolized using commercially available nozzles . 
Meaning of the word marked with <WSD> tags:  a small usually single-celled asexual reproductive body produced by many nonflowering plants and fungi and some bacteria and protozoans and that are capable of developing into a new individual without sexual fusion