Here's how to determine the complementary DNA strand:

Base Pairing Rules

DNA bases pair up in a specific way:

* Adenine (A) always pairs with Thymine (T)

* Guanine (G) always pairs with Cytosine (C)

Finding the Complementary Strand

1. Start with the given sequence: TCG AAG

2. Match each base with its complement:

* T pairs with A

* C pairs with G

* G pairs with C

* A pairs with T

* A pairs with T

* G pairs with C

3. Write the complementary sequence: AGC TTC

Therefore, the complementary strand of DNA for TCG AAG is AGC TTC.