Answer:
The polio strains cannot reproduce because they are weakened.
Theories explain phenomena, whilst laws are generalizations which characterize them.
Answer:
"The American Robin is the largest, most abundant and broadly distributed thrush in North America. The presence of this songster in the backyard setting, together with its loud, musical voice, make it one of the most recognizable birds in North America. Indeed, the American Robin has been described as "America's favorite songbird" (Young 2012)".
Hope this helps :)
1. <span>a. messenger RNA (mRNA)
2. </span><span>c. they have different sugars
3. </span><span>a. uracil
Hope this helps!</span>
