Crime-scene work often involves obtaining a DNA sample from a drop of blood to help identify persons who may have been involved. Frequently, the size of the DNA sample is extremely small, too small for easy analysis. Which of the following laboratory procedures could criminologists use to amplify the amount of DNA present? Cloning and gel electrophoresis Cloning and polymerase chain reaction (PCR) DNA splicing and polymerase chain reaction (PCR) Vector amplification and DNA splicing

Which of these is true of the cytoplasm of an unfertilized egg? a. it is an unevenly distributed mixture of mrna, proteins, organelles, and other substances. b. it does not contain substances that are important in directing development. c. these substances are supplied by the sperm. d. it does not contain substances that are important in directing development. e. development is directed solely by the surrounding cells. f. it is a homogeneous mixture of mrna, proteins, organelles, and other substances. g. it does not contain substances that are important in directing development. h. these substances are produced by the dna of the fertilized zygote.