Final answer:
The correct statement about fetal development is that fetal heart tones may be detected with a stethoscope by the 16th week.
Step-by-step explanation:
Factual Accuracy in Fetal Development
The fetal development of a human being is a complex process that spans approximately 38 weeks from fertilization to birth. With regard to the statements provided, the true statement regarding fetal development is A. Fetal heart tones may be detected with a stethoscope by the 16th week. This detection is possible due to the significant development of the fetal cardiovascular system at this stage.
Statement B, suggesting survival if born before the 20th week, is not accurate; as survival rates significantly increase after the 24th week when more of the fetus's vital organs are developed. Statement C states that by the 38th week, the baby is considered fully developed. Although the term 'fully developed' can be subjective depending on specific medical or developmental contexts, generally, birth around the 38th week is considered full-term with the baby's organ systems being sufficiently matured to function outside of the womb. Lastly, Statement D, which suggests the sex of the infant can usually be determined by 8 weeks gestation, is also incorrect. While sex determination is indeed part of fetal development, it typically becomes possible to identify on ultrasound around the 12th week.
Hence, when summarizing fetal development, especially regarding the capability to detect fetal heart tones, the vital growth stages and survivability of preterm birth, and sex determination, it's important to rely on the most current and scientifically verifiable data.