A researcher studying the human immunodeficiency virus (HIV) has infected human T cells with wild-type or Rev-deficient viruses. She extracts cytoplasmic RNA from the cells and separates each isolated RNA mixture by agarose-gel electrophoresis. She then uses northern analysis using HIV-specific probes to identify those bands that contain viral RNA. The results are presented in the following schematic drawing. Which lane (1 or 2) corresponds to cells infected with the Rev-deficient virus? What is the size of the full-length HIV genome?

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).

when it is at an intermediate population density

answer: grassland biomes are closer to the equator and receive more rain.

grasslands are biomes that are dominated by grasses rather shrubs and trees. savanna are biomes that exhibit grasses, shrubs and small tree as vegetation. grasslands are located near the equator of the earth. these are found in north america. savanna biomes are found in africa, south america, australia and india. grassland exhibit moderate climatic conditions, it receives   amount of rainfall higher than savanna.   therefore, savanna exhibit dry and hot climatic conditions.