Answer:
Red blood cells and the heart causes response to stimuli
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.
Answer:
Option 2 and 4
Explanation:
i think it is option 2 and 4 because it tells us what a character does :)
Answer:
meteorite striking the dinosaures