The correct answer should be additionally.
The word additionally would provide the best transition between these two sentence. It is so because you have one idea in the first sentence, and then you want to show another idea very similar to the first one in the second sentence. Using additionally to convey that is the way to go.
Although coal, hydrocarbons, iron ore, platinum, copper, chromium, nickel, gold and other minerals have been found, they have not been in large enough quantities to exploit. The 1991 Protocol on Environmental Protection to the Antarctic Treaty also restricts a struggle for resources.
<span>A postmodernist work is more likely to have B. a more playful attitude than a modernist work. This is because most of the modernist works revolved around the WWI, which was a dark and tragic time, and postmodernism started after the wars, so those were not a dominant topic of their literature. Thus, the authors could experiment more with the genre, be more playful, all the while still talking about serious topics, usually in a cynical and surreal way.</span>
Typically, a "how-to" speech is A, sequential, because it lists the steps in order.
Comment the correct answer.