believe X as Y is an incorrect idiom.
Correct idiom is
believe X to be Y
have a look at the following official SCs( emphasized parts)
Providing initial evidence that airports are a larger source of pollution than they were once believed to be, environmentalists in Chicago report that the total amount of pollutant emitted by annually by vehicles at the O'hare International airport is twice as much as that which is being emitted annually by all motor vehicles in the Chicago Metro area
A) as much as that which is being emitted annually by all
B) as much annually as is emitted by the
C) as much compared to what is annually emitted by all
D) that emitted annually by all
E) that emitted annually compared to
OA D
The new image of Stone Age people as systematic hunters of large animals, rather than merely scavenging for meat, have emerged from the examination of tools found in Germany, including three wooden spears that archaeologists believe to be about 400,000 years old.
(A) merely scavenging for meat, have emerged from the examination of tools found in Germany, including
(B) as mere scavenging for meat, have emerged from examining tools found in Germany, which include
(C) as mere meat scavengers, has emerged from examining tools found in Germany that includes
(D) mere scavengers of meat, has emerged from the examination of tools found in Germany, which includes
(E) mere scavengers of meat, has emerged from the examination of tools found in Germany, including
OA E
On Earth, among the surest indications of sunspot cycles are believed to be the rate that trees grow, as seen in the rings visible in the cross sections of their trunks.
A. On Earth, among the surest indications of sunspot cycles are believed to be the rate that trees grow
B. On Earth, among the surest indications of sunspot cycles are, it is believed, the rate of tree growth
C. On Earth, the rate at which trees grow is believed to be among the surest indications of sunspot cycles
D. Among the surest indications on Earth of sunspot cycles, believed to be the tree growth rate
E. Among the surest indications on Earth of sunspot cycles is believed to be the rate at which trees grow
OA E