Answer:
B
Explanation:
Many organs such as stomach, teeth, are some things that make up the digestive system.
remember: organelles -> cells -> tissue -> organ -> organ system -> organism.
The correct answers are:
• Human bodies may contain pathogenic bacteria, but these are often kept in check by other (nonpathogenic) species.
• Human bodies contain bacteria that are beneficial to certain processes (for example, digestion).
Non-pathogenic species or normal flora are present in the different parts of human body such as oral mucosa, skin, seminal fluid, uterus, lungs, saliva.. Microbiota of normal flora are usually commensal (co-exist without harming effects on humans) whie some of them even have a mutualistic relationship with their human hosts (benefits for both) such as those hosted in the intestine.
