The answer for this question would be Integument, digestive, respiratory and urogenital.
The largest system that contact with the external environment would be integument and digestive. That makes two system has normal flora of microbes and not sterile like the other systems. Normal flora of microbes will prevent the pathogen microbe grows so it gives some benefit.
The abdominopelvic is composed of the abdominal cavity and the pelvic cavity. This cavity contains the organs such as liver, stomach, spleen, gallbladder, pancreas, kidney and most of the intestines along with the internal reproductive organs and urinary tract. The navel is located in the umbilical region of the abdominopelvic cavity.
Hence, the blank can be filled with 'umbilical region'.
Answer:
D. Which cell organelles carry out the process of photosyinthesis and cellular respiration?
