4 Is it possible for a plant to be photosynthesising and respiring at the same time
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Photosynthesis occurs only during the day in plants and algae , cellular respiration occurs both Night and Day . The two processes take place in different cellular organelles (The cholroplast and mitochondria , respectively and occur simultaneously)

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).