1. double-ringed bases are purines exempt from chargaff's rules complementary with each other pyrimidines 2. which of the following is not a characteristic of chargaff’s rule #1? is also termed chargaff's ratio states that t = a and g = c states that dna composition varies among species states that the ratio of adenine to thymine is equal, as is the ratio of guanine to cytosine 3. what type of bonds are formed between complementary bases? triple carbon to carbon bonds hydrogen bonds ionic bonds polar covalent bonds 4. are single-ringed bases. guanines adenines purines pyrimidines