CST NB Entry #1—DNA In a strand of DNA, adenine always pairs with ______ and guanine always pairs with _______ A. Thymine, uracil B. Thymine,guanine C. Uracil, cytosine D. Thymine, cytosine

NB Entry #2—Genetics Genes on the Y chromosome are important for the normal development of A. Both boys and girls B. Girls only C. Neither boys nor girls D. Boys only

NB Entry #3—Meiosis Which describes the cells produced by meiosis? A. Diploid sex cells B. Haploid sex cells C. Haploid body cells D. Diploid body cells

NB Entry #4—Genetic Change How does fertilization increase genetic variation? A. By leading to natural selection B. By causing new mutations to occur C. by creating new allele combinations D. by allowing crossing-over to occur

NB Entry #5—Genetic Variation What contributes to genetic variation in sexually reproducing species? A. Shuffling of genes and chromosomes during gamete formation B. Mutations creating new life forms C. variation in environmental conditions D. all of the above

NB Entry #6—Immunity Which of the following is an example of a non-specific defense A. Killer T-cell production B. Cell-mediated immunity C. humoral immunity D. the skin