How Identical Is Identical?


Everyone knows that identical twins look alike, night? Not quite. Although it may be very hard to tell identical twins apart, no two people are exactly the same even identical twins. Identical twins develop from the same fertilized egg, so they share the same genes. Genes contain the information that determines people's physical traits. While most people have their own unique set of genetic instructions, identical twins are unusual because they both have the same set. But researchers have discovered that those instructions do not tell the entire story. The environment in which each twin grows and develops also affects many aspects of their physical appearance and personality. Even small differences can have considerable effects. Fingerprints are a good example. One might assume that identical twins have the same tingerprints. But detectives have known for many years that this is not the case. Like snowflakes, no two fingerprints are alike. Unique pattems on the tips of the fingers appear as the child develops in the womb. While genetic instructions are the primary influence on fingerprint pattems, researchers have discovered other factors that also have an impact. The rate of bone growth, or environmental factors such as pressure in the mother's womb and contact with fluid, can also affect the developing twins' fingerprint patterns. So even though two twins grow next to each other in the womb, they experience slightly different environments. As a result, they develop slightly different fingerprints.











1. According to the author, the fact that twins do NOT have identical fingerprints prove that_________.

A.they are not actually twins

B.no two people are exactly alike

C.genetic patterns do not affect appearance

D.twins often have different personalities






2. Which of the following is NOT an environmental factor that can still affect fingerprint patterns? *

A.contact with fluid

B.rate of bone growth

C.pressure in the womb

D. how twins are raised





3. Evidence in the passage suggests that_______.

A.twins often have the same thoughts

B.the shape of snowflake is determined by genes

C.environmental affects people more than their genes do

D.genetics and environment affect growth



4. Evidence in the passage suggests that the physical differences between identical twins are usually_______.


A.significant

B.impossible to determine

C.measured after birth

D.small



5. What makes having unique fingerprints a positive quality?

Your answer:​