The organs of the heart and the blood vessels form which of the followings ?

a. a cell
b. a tissue
c. an organ
d. an organ system

How does pregnancy begin? a) a placenta forms in the uterus b) a sperm reaches an egg in the fallopian tubec) the blastocyst differentiates into two cell types d) contractions begin in the uterine wallapex

Which kind of mutation has occurred when the codon for an amino acid is changed to a stop codon? a. a silent mutation b. a missense mutation c. a frameshift mutation d. a nonsense mutation

Which of the following describes research that would be considered basic science? a. a farmer is trying to improve his crop yields by using a new kind of fertilizer. b. a college students is curious about the growth of desert pants in the presence of excess amounts of water. c. government officials are trying to prevent the spread of new strain of influenza virus. d. a doctor is trying to determine why a patient is feeling tried and sick. b.a college students is curious about the growth of desert pants in the presence of excess amount of water