Q: A sequence of amino acids in single polypeptide is the primary structure for what? Choices: - lipids - cells - dna - proteins A:
proteins

Q: In winter, water does what, becoming solid and causing hoses to rupture and engine blocks to crack? Choices: - crystallizes - shrinks - fractures - freeze A:
freeze

Q: Q: What are the smallest type of blood vessel? Choices: - varicose veins - spider veins - arteries - capillaries A:
A: capillaries

Question: Q: What percentage of all species that ever lived on earth have gone extinct? Choices: - 25% - 50% - 93 % - 99% A:
Answer: 99%

*Question*
Q: What is contained in the cavity of a long bone's central shaft? Choices: - blood - calcium - cells - marrow A:
**Answer**
marrow

(Q).
Q: What do you call a device that produces a very focused beam of visible light of just one wavelength and color? Choices: - optical diffuser - fusion relay - light meter - laser A:
(A).
laser