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.
Complementarity between two antiparallel strands of DNA. The top strand goes from the left to the right and the lower strand goes from the right to the left lining them up. Left: the nucleotide base pairs that can form in double-stranded DNA. Between A and T there are two hydrogen bonds, while there are three between C and G. Right: two complementary strands of DNA.