A DNA molecule in which both strands have radioactive thymidine is allowed to duplicate in an environment containing non-radioactive thymidine. What will be the correct number of DNA molecule that contain some radioactive thymidine after 3 duplications?

Sulphur has allotropic forms . Which of the following is not true? (1)Rhombic sulphur changes to monoclinic at 369 K and at this temperature both form exist. (2)Both alpha and beta forms containS8 molecules having crown structure heating to 600°C, becomes diamagnetic (3)Sulphur also exist as S6 chair form with S-S bond length 205.7 pm and angle 102.2