Where are many foods imported from during our winter? Why can they grow food when we can't?

It’s obvious to anyone who visits an American supermarket in winter — past displays brimming with Chilean grapes, Mexican berries and Vietnamese dragon fruit — that foreign farms supply much of our produce.

Imports have increased steadily for decades, but the extent of the change may be surprising: More than half of the fresh fruit and almost a third of the fresh vegetables Americans buy now come from other countries.

Although local, seasonal and farm-to-table are watchwords for many consumers, globalization has triumphed in the produce aisle. And despite the protectionist “America First” message coming from the Trump administration, the growth in imports appears likely to continue.

So this is an apt moment to examine how the shift happened, and what it portends — good or ill — for American consumers and farmers.

“I had no idea that more than half our fruit is imported, and it shocks me that this has happened so quickly,” said Michael Pollan, a professor of journalism at the University of California, Berkeley, whose best-selling books have analyzed the tensions between local and global food systems

Explanation:

why do the isotopes of a particular element behave differently in nuclear reactions but the same in chemical reactions? chemical reactions involve changes to electrons in an atom; isotopes do not differ in electrons, and so they react the same way during chemical changes.

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.