Answer:
Septa and the internal crosswalls.
Step-by-step explanation:
Rhizopus stolonifer, also known as the black bread mold, is a fungus in the Mucoraceae family that causes soft rot in plants and fruits. This fungus is widely distributed worldwide and can often be viewed on bread and lemon surfaces. Unlike most fungi, Rhizopus stolonifer's cells lack the septa and the internal crosswalls.