You want to map the positions of three genes (x, y, and z) all found on one chromosome in drosophila. each gene has one dominant allele and one recessive allele. you perform the three different two-factor crosses (cross 1: xy and xy, cross 2: yz and yz, and cross 3: xz and xz). assume all crosses are between diploid flies homozygous for the alleles of these genes. you observe 7% recombinants in the first cross, 20% recombi- nants in the second cross, and 13% recombinants in the third cross. draw a map placing the genes in the proper order and give the distance between each gene in map units (m.

the abdomen (less formally called the belly, stomach, tummy or midriff) constitutes the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. the region occupied by the abdomen is termed the abdominal cavity. the stomach secretes acid and enzymes that digest food. ridges of muscle tissue called rugae line the stomach. the stomach muscles contract periodically, churning food to enhance digestion. the pyloric sphincter is a muscular valve that opens to allow food to pass from the stomach to the small intestine.

"do a testcross with a homozygous recessive plant."

answer: substrate concentration. enzymes work best when there is a high enough substrate concentration for the reaction they catalyse.