Answer:
High nutrient pollution (fertilizer) in run off from the land caused an increase in algae that live on the surface.
Explanation:
Hello. The answer is zinc.
The control group in this experiment is the group of tomatoes that do not receive any fertilizers i.e. fourth tomato plants.
<h3>What is Fertilizer?</h3>
Fertilizer may be defined as any chemical or natural substance which is added to the soil with the intention of enhancing productivity.
All those groups of tomatoes in which fertilizers are added behave as a reference group while those in which fertilizer is not added behave as a control group.
Therefore, it is well described above.
To learn more about Fertilizers, refer to the link:
brainly.com/question/24544067
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Answer: The correct answer is - 3) olfactory receptors neurons that detect smell. 4) photoreceptors neurons that detect light .
1) and 2) statements are correctly matched in the question..
Olfactory receptors are also called odorant receptors. The olfactory receptor neurons detect smell and thus give a sense of smell to the organism. They are present in the nasal cavity.
Photoreceptor neurons are those that detect light and they are present in the retina of eye.
