【单选题】Reinventing the Table An earth scientist has rejigged the periodic table to make chemistry simpler to teach to students. (46)But Bruce Railsback from the University of Georgia3 says he is the first to...
A.
There have been many attempts to redesign the periodic table since Dmitri Mendeleev2 drew it up in 1871.
B.
Railsback has still ordered the elements according to the number of protons they have.
C.
'I imagine this would be good for undergraduates.'
D.
Railsback has listed some elements more than once. E And the size of element's symbol reflects how much of it is found in the Earth's crust. F The traditional periodic table was well drawn.
【单选题】It has been known for many decades that the appearance of sunspots is roughly periodic, with an average cycle of eleven years. Moreover, the incidence of solar flares and the flux of solar cosmic rays...
A.
two competing scientific models concerning the sun's magnetic field
B.
an overview of some recent scientific developments in solar physics
C.
the reasons why a problem in solar physics has not yet been solved
D.
the difficulties involved in linking terrestrial climate with solar activity