The sides of the DNA ladder consist of alternating and phosphates

sugar

Explanation:

The sides of the stepping stool are made of rotating sugar and phosphate particles. The sugar is deoxyribose. The rungs of the stepping stool are sets of 4 sorts of nitrogen bases. Two of the bases are purines-adenine and guanine.

kelp are large brown algae that live in cool, relatively shallow waters close to the shore. they grow in dense groupings much like a forest on land. these underwater towers of kelp provide food and shelter for thousands of fish, invertebrates, and marine mammal species.

e) all of the above