Relationship of the Study physiological responses and physical sports aerobic and anaerobic in the light of genetic code differences in angiotensin Researcher: Belal Badr Eldin Mohamed Mohamed  Research Problem and Significance:: The renin-angiotensin system, in its classic definition, is known as an endocrine system that exerts its actions through the effector peptide, angiotensin II, in various organs to act as a vasoconstrictor and a regulator of salt and volume homeostasis. When renal blood flow is reduced, juxtaglomerular cells in the kidneys convert the precursor prorenin, already present in the blood, into renin and secrete it directly into the circulation. Plasma renin then carries out the conversion of angiote-nsinogen, released by the liver, to angiotensin I. Angiotensin I is subsequently converted to angiotensin II by the angiotensin-converting enzyme (ACE) found in the lungs. Angiotensin II is a potent vasoconstrictive peptide that causes blood vessels to narrow, resulting in increased blood pressure. Angiotensin II also stimulates the secretion of the hormone aldosterone from the adrenal cortex. Aldosterone causes the renal tubules to increase the reabsorbption of sodium and water into the blood, while at the same time causing the excretion of potassium (to maintain electrolyte balance). This increases the volume of extracellular fluid in the body, which also increases blood pressure. Furthermore, angiotensin II directly increases norepinephrine secretion in the sympathetic ganglia, which enhances the sensory organs' responsiveness to the athlete's training and skill execution.Previous studies have yielded conflicting results regarding the association of the (II) genotype with endurance and maximal oxygen uptake (VO2 max), as well as the association of the (DD) genotype with speed. Meanwhile, other studies found no association between the ACE (II/DD) genotypes and the aforementioned variables. This significant discrepancy in the literature motivated the researcher to investigate the relationship between different ACE genotypes and physiological and physical responses, in an attempt to bridge the gap between the field of sports training and genetic biotechnology.  Research Objectives: The primary objective of this research is to identify the relationship between physiological and physical responses to aerobic and anaerobic activities in light of the angiotensin-converting enzyme (ACE) genotypes, by achieving the following sub-objectives: 1. Identifying the different ACE genotypes among the research sample. 2. Determining the physiological and physical responses of the research sample following the administration of aerobic and anaerobic tests. 3. Identifying the differences among participants with the three ACE genotypes (II, DD, and ID) regarding physiological and physical responses following the administration of aerobic and anaerobic tests.  Research Hypotheses: 1. There is a variation in the prevalence of angiotensin-converting enzyme (ACE) genotypes among the members of the research sample. 2. There are variations in the physiological and physical responses following the administration of aerobic and anaerobic tests among participants with different ACE genotypes (II, DD, ID). 3. There are statistically significant differences among subjects with different ACE genotypes (II, DD, ID) regarding specific physiological and physical responses following the administration of aerobic and anaerobic tests.  Methodology: • Research Design & Sample: The researcher utilized the descriptive method [Note: Change to 'experimental method' if that is what you actually used], as it aligns with the nature of this research. The total sample consisted of 20 students aged 18 years. Ultimately, 13 students were selected as the primary sample and were categorized into three groups based on their ACE genotypes (II, DD, ID).  Data Collection Methods: • Tools and Equipment: Medical scale - Stadiometer - Stopwatch - Polar heart rate monitor - Spirometer - Sphygmomanometer (Sejoy) - Micropipette - Spin column - Sodium edetate tubes - Syringes - PCR Master Mix - Thermo-Hybaid PCR Express Thermal Cycler - UV Transilluminator - Shaker incubator. • Physiological Measurements: Vital capacity (pre- and post-effort) - Relative maximal oxygen uptake (VO2 max) - Absolute maximal oxygen uptake - Systolic and diastolic blood pressure (pre- and post-effort) - Heart rate (pre- and post-effort) - Energy index (pre- and post-effort) - Physical efficiency - Myocardial oxygen consumption index (pre- and post-effort). • Applied Tests: 30-meter sprint - Three consecutive broad jumps - Step box test (to measure anaerobic capacity, VO2 max, and physical efficiency) - Sargent vertical jump test - Quadrant jump test (10 seconds).  Conclusions and Recommendations: • Conclusions: Within the limitations of the research sample, the researcher concluded the following: 1. ACE genotypes are associated with specific physiological responses and physical performance following aerobic and anaerobic activities. 2. Participants with the ACE (II) genotype demonstrated superior physiological responses (specifically, post-effort heart rate and relative VO2 max) compared to those with the (DD) and (ID) genotypes. This indicates an association between the ACE (II) genotype and specific aerobic capacities, which serve as indicators of endurance. 3. Participants with the ACE (DD) genotype exhibited superior physical responses in maximum speed (30m sprint) and agility (10-second quadrant jump) compared to those with the (II) genotype. Similarly, participants with the (ID) genotype outperformed those with the (II) genotype in maximum speed (30m sprint). This suggests that the ACE (DD) and (ID) genotypes are associated with specific anaerobic capacities, which act as indicators of speed and require rapid, repetitive muscle contractions. • Recommendations: 1- Guiding young people with genetic code (II) to practice aerobic activities. 2-Guiding young people with genetic code (DD,ID) for anaerobic activities. 3 - Carrying out analyzes of endurance or speed genes through group research (working groups) and not individual research, because of the high costs in the analysis of these genes. -4Conducting such research on larger human samples and in different mathematical disciplines so that the results can be generalized. -5Study different types of genes and identify the genes responsible for the superiority of athletes in physical and physiological determinants