Oxygen - It is very important for all living to survive 'cause without it, cellular respiration can't take place....
Glucose - It is the simple food, it provides energy to the whole ecosystem, so that they can survive.
Without either of them, life is not possible!!!!!
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Answer:</h3>
Vertebrates have backbones, while invertebrates do not.
Humans, for example, are vertebrates because we have backbones.
Answer: C & A
Explanation:
The HOX genes encodes important transcription factors. This factors causes protein to be made that specify cell fate and identify; embryonic primary axis, secondary axis and plays important roles in various tracts development.
The answer should be advantame
