Question

question 2
to guarantee the validity of experimental results, scientists rely on precise, unchanging standards of measurement. ______ metrologists (scientists who study measurement) developed the si, or international system of units. the sis units of measurement are based on unchanging values in nature, such as the mass of an electron or the speed of light.
which choice completes the text with the most logical transition?
a) in contrast.
b) regardless.
c) in addition.
d) for this reason.

Explanation:

The first part states scientists need precise measurement standards. The second part says metrologists developed the SI system for this purpose. "For this reason" shows a cause - and - effect relationship. "In contrast" shows opposition, "Regardless" indicates ignoring something, and "In addition" adds more information without a cause - and - effect link.

Answer:

D. For this reason