Amurder has occurred, and you are asked to solve it. the police bring you a sample from the crime scene of what they believe is the killer's dna and ask you for a chemical analysis. your study of this sample reveals the presence of adenine, thymine, ribose, and uracil, leading you to conclude that the sample is
a) pure dna.
b) pure rna.
c) probably a mixture of dna and rna.
d) probably a mixture of rrna and mrna.
e) definitely not from the killer.

c) probably a mixture of DNA and RNA.

Explanation:

DNA and RNA are the two types of nucleic acids present in cells. DNA or deoxyribose nucleic acid is composed of four type of bases ( adenine, thymine, guanine and cytosine ), deoxyribose sugar and phosphate group. RNA or ribose nucleic acid is composed of four types of bases ( adenine, uracil, guanine and cytosine), ribose sugar and phosphate group.

Here, the sample had adenine which could be either from DNA or RNA. Thymine is from DNA. Ribose sugar is from RNA and uracil is from RNA. Hence, the sample has a mixture of DNA and RNA.  

a- all cells come from pre-existing cells

after a the power stroke, adp is released, but the cross-bridge formed is still in place. atp then binds to myosin, moving the myosin to its high-energy state, releasing the myosin head from the actin active site.