What’s the main idea of the passage?

Like people who share news via Twitter, Facebook and Linkedln, cells, too, make use of multiple modes of information exchange. Some send out hormones, which travel far and wide via the bloodstream; others emit neurotransmitters, which carry signals between one neuron and another. But virtually all cells network with their neighbors via extensive collections of channels that directly connect the inside of one cell with the inside of the next.

It’s predicted that, by the year 2037, there will be 77, 000 women and 34, 000 men in the U. K. who have reached their centenary. Hard though it is to believe, one-third of all children born in 2013 in the U. K. will one day find themselves blowing out 100 candles on their birthday cake — although there won’t be quite as many men at those parties as women.