Answer: Low oxygen content.
Explanation:
There are many dangers to the survival of fish in shallow water that depend on the properties of water.
1. The oxygen content drops during the winter and also in hot weather. Fish cannot survive without enough oxygen in the water.
2. High evaporation rates can drain the pond.
3. Fortunately, water has a high thermal mass, so overheating the water to the boiling point is not an issue.
Of the three reasons given, lack of oxygen is the most critical.
So if it's 20% adenine (A) then it's 20% (T)...because A always pairs with T. That adds up to 40%....60% therefore is G+C...so you'd have 30% Cytosine (C) and 30% Guanine (G).
All cells have at least one strand of DNA. prokaryotic cells are single celled, plants have a cell wall and vacuoles, animal cells have a centrosome. smooth or: synthesize lipids, metabolized carbohydrates, store calciumrough or: has bound ribosomes, produces proteinsGolgi apparatus: flattened membrane sacs, modifies products of the ER manufacturers macromolecule sorts. lysosomes: membrane sac of hydrolytic enzymes, hydrolyzes proteins, mitochondria: power house of the cell, makes ATP and such chloroplasts: allows photosynthesis to be a thing