Fire and Mello conducted an experiment where they added no gene X RNA (b), anti-sense gene X RNA (c) or double stranded gene X RNA (d) to C. elegans embryos. They then did a hybridization experiment examining gene X mRNA levels in the embryo. Square (a) is a no probe control. How does this act as a control?

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.

if you know your abc's you should be able to get your answer or just use google