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Koreans succeed in cloning human embryos
Level 1 |
Elementary
4
Fill the gaps using a preposition.
1.
Scientists take DNA ______ one egg and put it ______ another egg.
2.
______
the first time, they have cloned a human embryo.
3.
They replaced the DNA ______ chromosomes from an adult egg.
4.
This research could lead ______ treatment for serious diseases.
5.
Scientists have been working ______ cloning research for many years.