a group of 625 students has a mean age of 15.8 years with a standard deviation of 1.2 years. the ages are normally distributed. about how many students in this sample are younger than 17?

Did the universe cool off or get hotter as it expanded after the 'big bang"?

The chart below matches messenger rna codons with amino acids. a dna strand has the sequence of bases, aat. according to the chart, the corresponding messenger rna codes for which amino acid?

Rick is on a bicycle trip. every 4 days he bikes 230 km. if rick keeps this same pace for 16 days, how many kilometers will he bike?