Your examples are a little casual, but it's not wrong to use them in written English.
Between "there are lots of kinds of
primates" and "there are many
," the GMAT would definitely prefer the latter. However, you are unlikely to have to make such a decision. If "lots of" were used on the GMAT, it would likely be used in the non-underlined section or in every choice.
Emily Sledge | Manhattan GMAT Instructor | St. Louis
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