To estimate the expansion rate of the universe is a notoriously difficult problem because there is a lack of a single yardstick that all distances can be measured by .
(A) To estimate the expansion rate of the universe is a notoriously difficult problem because there is a lack of a single yardstick that all distances can be measured by.
To estimate is incorrect - in the current sentence usage.
a lack of a single yardstick - can be written precisely as "no single yardstick". Incorrect
...
(A) To estimate the expansion rate of the universe is a notoriously difficult problem because there is a lack of a single yardstick that all distances can be measured by.
To estimate is incorrect - in the current sentence usage.
a lack of a single yardstick - can be written precisely as "no single yardstick". Incorrect
...
.jpg)
