While at an amusement park, you inhale helium from a balloon to make your voice higher pitched. a friend says that helium reacts with and tightens the vocal cords to make your voice have the higher pitch. could he be correct? why or why not?

Which of the following would be least likely to support the modern concept of biological evolution? ( 2 points) a)different species of organisms with similar bone patterns b)different species of organisms with similar reproductive rates species in c)different domains with similar metabolic pathways species in d)different kingdoms with similar cellular structures.

What does it mean for a cell membrane to be selectively permable

Which of these is one of the nitrogenous bases in dna? a. proline b. leucine c. glycine d. thymine