Which best describe the structure of dna?
a.) purine backbones with pyrimidines on the inside.
b.) base backbones with sugar on the inside.
c.) sugar-phosphate backbones with bases on the inside.
d.) a backbone of bases with phosphate groups on the outside.

Ricardo notices that when he plays soccer in the rain, his ball does not seem to go as far after a kick. what is the best scientific question that ricardo could ask about this observation? is soccer better played in the rain or sun? how does rain affect the distance a soccer ball can travel? how does rain affect the speed of a soccer ball? is soccer affected by the rain?

(select all the correct choose each statement that is scientific. - the opinions of randomly selected participants in a survey prove the idea that global temperatures are not increasing on earth. - the universe's average temperature and rate of expansion support the idea that it began as one super-dense and hot mass 13.8 billion years ago. - ocean tides are caused by the uneven gravitational pulls of the moon and sun on different parts of earth. - human life is more valuable than other forms of life on earth because humans are more intelligent than other organisms.

The activity of the modern sample is 1.10 bq . how long does that measurement take?