Their refusal to do any type of military service.
Answer:
Environmental instability may have been a factor not only in shaping adaptations but also in contributing to the extinction of some lineages. Environmental variability associated with the extinction of large mammal species has been proposed for the southern Kenya region.
<span>One
of biggest obstacles to improving their lives that the Native Americans faced
in the 1950s was racism</span>. Native Americans were
impeded from obtaining better standards of living as they were discriminated
against on the basis of their race. This practice greatly prejudiced the Native
Americans during this epoch.
The skepticism about the empire of Ghana and the accounts for it is nothing weird because the majority of what is written about it is from two people from the same place, that had totally different views and interpretations on the things, and came from different culture.
Very often in the historical text, the people that wrote something have been very subjective, not objective. Thus the writings of these two Arab geographers can be very misleading, as they described what they saw with their own eyes, but also with using their own perception. That has proven numerous times to give very inaccurate depictions of a society and culture, like the depictions of the Romans for the Celts, or of the Greeks for the Scythian female warriors that they named Amazons.
There's only one point of view unfortunately, and it is always much more reliable when multiple writings are available from people from multiple different backgrounds, or the best scenario if it is writings from the people in question.
assuming efficiency of each man to dig trench, in one day, for one hour is constant,
so one man, working for one hour in one day can dig 1.5 m
so 8 men, working 3 hours a day and will take, say $d$ number of days and efficiency will be constant. so,
$\frac32=\frac{220}{8\times3\times d}$
$\implies d=\frac{55}9=6.12$
