1 n Americans before admixture is also subject to doubt.

2 iate between experimental treatments is open to doubt.

3 ve epistasis is ubiquitous, and this has led to doubts about its importance in biological evolution.

4 unodeficiency virus (HIV) infection have led to doubts about the adequacy of the recommended penicill

5 w infection has been uncertain, contributing to doubt regarding the utility of experimental challenge

6 nefits vary widely, and there may be reasons to doubt that claims of efficacy reflect real-world effe

7                                 This has led to doubts that Mars can be described adequately using th

8                       There are good reasons to doubt whether presently recognized prokaryotic specie