What’s the mean oxygen level for cold ponds?

Why do german shepherds shed so much

Coral reefs support more species per unit area than any other marine environment on earth. what is one way coral reefs are important to the health of the biosphere

How do you know that the plant cells in these two images have different jobs, or functions? a. because all plant cells serve different functions b. because they are two different colors c. because their dna are different d. because their structures are different