About Tac Light. Tac Light is a small-but-powerful flashlight by Bell & Howell that has been advertised on television in 2016. The official product website is trytaclight.com, which was registered in April 2016. The screenshot below was taken of the official website in May 2016. 22 times brighter than regular flashlights (600 lumens)
However, only four bases: A (adenine), C (cytosine), G (guanine), and T (thymine) constitute the backbone of the molecule. The DNA molecule is made up of two polynucleotide strands intertwined together to form a long helical structure, the DNA double helix.
The two strands of DNA stay together by H bonds that occur between complementary nucleotide base pairs. Two hydrogen bonds occur between the adenosine and the thymine base pairs, and between the cytosine and the guanine there are three.