Answer: The steps are made of nitrogenous bases; deoxyribose sugars linked with phosphates.
Explanation: The rungs of the DNA are made of nitogenous bases (The nitrogenous bases are adenine (A), thymine (T), guanine (G) and cytosine (C) ) they are held together by weak hydrogen bonds.
The railings of the DNA are made of deoxyribose sugars which are alternating with phosphates. This part of the molecule is referred to as the "backbone".
The products that are derived from invertebrates are the following:
1. food - crabs, lobsters, oysters, octopuses: all of these are invertebrates (meaning they have no spine) and are used as food
2. shell - seashells are invertebrates and their shells are used for various purposes
3. jewelry - shells are used as jewelry, as well as pearls coming from seashells
4. silk - silk comes from silkworms, which are invertebrates
I just wouldn't pick cotton, because you get cotton from a plant.
Im not sure if this will be the answer you teacher is looking for but i think the answer would be
Hair on the head protects scalp from injury and sunlight
Eyelashes and eyebrows protect eyes
Nostril and ear hairs protect from foreign particles
