1.Stars shine because of _______

1.Stars shine because of _______
produced by the nuclear reactions
taking place within them.
(A) the amount of light and heat is
(B) which the amount of light
and heat
(C) the amount of light and heat
that it is
(D) the amount of light and heat
但我觉得是A,如果选D的话,produced在这里是谓语吗
下面是改错题,加括号的地方是有错误的,请问怎么改正?
19.Geographers were once concerned largely with exploring areas unknown to them
A B
and （from） describing distinctive features of individual places.
C D
21.The first city in the United States that put into effect major （plan） for the clustering,of
A B C
government buildings was Washington,D.C.
35.35.Physicians working in the field of public health are mainly concerned with the
A B
environmental causes of （ill） and how to eliminate them.
此题有疑问,我觉得concerned是不是应该改为concerning呢,应为前面有个are.
38.Astronomers use photography and sighting telescopes to study the motions of all of
A B C
the bright stars and many of the faint one.
此题我知道应该把one改成ones,但是of all of the bright第二个of 是不是多余了?
D