Related Questions
Correct Answer is A
Explanation
Choice A Reason: Trisomy numeric abnormality. Down syndrome is a genetic disorder that occurs when a person has three copies of chromosome 21 instead of two. This extra chromosome causes various physical and mental features that vary from person to person. Down syndrome is also called trisomy 21 because it involves three copies of chromosome 21.
Choice B Reason: Multifactorial inheritance is incorrect because it refers to a type of genetic disorder that results from the interaction of multiple genes and environmental factors. Examples of multifactorial disorders include cleft lip or palate, neural tube defects, diabetes, hypertension, and some types of cancer.
Choice C Reason: X-linked recessive inheritance is incorrect because it refers to a type of genetic disorder that affects males more than females because it is caused by a mutation on the X chromosome. Females have two X chromosomes, so they can be carriers or affected depending on whether they inherit one or two copies of the mutated gene. Males have one X chromosome and one Y chromosome, so they are always affected if they inherit the mutated gene from their mother. Examples of X-linked recessive disorders include hemophilia, color blindness, and Duchenne muscular dystrophy.
Choice D Reason: Chromosomal deletion is incorrect because it refers to a type of genetic disorder that occurs when a part of a chromosome is missing or deleted. This can cause various physical and mental problems depending on the size and location of the deletion. Examples of chromosomal deletion

Correct Answer is B
Explanation
Choice A Reason: Nagele's rule is a formula that estimates the due date by subtracting three months from the first day of the last menstrual period and adding seven days. However, this method assumes a regular 28-day cycle and may not be accurate for women with irregular cycles or who are unsure of their last menstrual period.
Choice B Reason: Ultrasound is the most accurate method of determining the estimated due date, especially in the first trimester. Ultrasound uses sound waves to create an image of the fetus and measure its size and development. Ultrasound can also detect any abnormalities or complications that may affect the pregnancy.
Choice C Reason: Gestation wheel is a circular calendar that estimates the due date by aligning the first day of the last menstrual period with a corresponding date on the wheel. However, this method also assumes a regular 28-day cycle and may not account for variations in ovulation or implantation.
Choice D Reason: Birth calculator is an online tool that estimates the due date based on various factors such as the last menstrual period, cycle length, ovulation date, conception date, or ultrasound date. However, this method may not be reliable as it depends on the accuracy of the input data and the algorithm used by the calculator.

