Which characteristic do plants, people and flatworms share?
a). they exchange gases with the environment
b). they all have digestive systems that break down food
c). they all undergo photosynthesis
d). they all use a muscular system for movement

Option A

Explanation: Plants, flatworm and people share the similar characteristics as they exchange gases with the environment.

The exchange of gases from the environment takes place differently in different types of organisms.

In case of flatworm it takes place through its skin, plants exchange gases through their leaves and animals respire through lungs.

The common character shared by all the three organism is exchange of gases.

step 1 ammonium can be absorbed by plants, but some is converted into nitrates which are better for plants to absorb. this is called nitrification. 2. step 2 the deer eats the plants and uses the nitrogen-containing proteins for cell growth. 3. step 3 bacteria in the soil conduct nitrogen fixation to convert nitrogen gas from the atmosphere into ammonium. 4. step 4 some of the nitrates are absorbed back into plants, but denitrification breaks down the nitrates into nitrogen gas released back into the atmosphere. 5. step 5 nitrogen is found in the urine, which gets broken down into ammonium through the process of ammonification. 6. step 6 plants absorb the ammonium and begin assimilation, the process to add the nitrogen to protein.