[Solved] In a Fischer projection,the horizontal bonds are assumed to go into the page. Occult Blood: Blood not visible to the naked eye, often detected in stool or urine samples to diagnose conditions such as gastrointestinal bleeding. Colon Cancer: A type of cancer that begins in the large intestine (colon), often detected through screening methods like colonoscopies. Screening Tools: Screening tools are instruments or tests used to identify the presence of diseases, conditions, or risk factors in individuals who do not yet show symptoms. Occult Blood: Blood that is not visible to the naked eye, typically detected through specific medical tests in stool, which can indicate gastrointestinal issues.