The compound butanol has the following structural formula. A string of 4 C atoms are bonded above, left, and below to H. The right-hand end is bonded to O, which in turn is bonded to H.

Which of these is a structural isomer of butanol?
A string of 4 C atoms are bonded above, below, left and right to H.
A string of 4 C atoms is bonded above, below, left, and right to H, except the second C, which is bonded below to O, which is bonded below to H.
A string of 4 C atoms is bonded above, below, left, and right to H, but the chain is interrupted between the first and second C, which are bonded to an O between them.
A string of 4 C atoms is bonded above, below, and left to H, except the last C has no H below and is double-bonded to an O to the right.

under a microscope, cancer cells may look very different from normal cells. they often have different sizes and some may be larger than normal while others are smaller. cancer cells are often abnormally shaped and the control centre of the cell (the nucleus) may have an abnormal appearance.

i think? ?

on passing the small ampere of electric current through the tube made of ar and hg of cfl generates uv rays which excites the fluorescent and thus emits the high radiation by consumption of just 5- 12 w in comparison to incandescent light which requires more power such as around 40 - 55 w to lighten.

moreover the life span of fluorescent or cfl is around 8000 h whereas the life span of incandescent is around 1200 h

hence, the building installed with incandescent lights bears more electricity bill.