The two strands of a dna molecule are said to be anti parallel. what dose the mean ?

Why are scientists concerned about the depletion of the ozone levels in the stratosphere?

What is the process by which biological parents pass traits such as hair type or eye color to their children

Which genetic disorders, caused by an extra x chromosome (xxy), is characterized by a lack of testicular development in males, effeminate features, possible mental impairment, and a thin stature?