Benjamin could hold difficult yoga poses for minutes, which impressed the less fit Leslie, since 
OPTIONS:
- Benjamin was so clumsy by comparison.
- Leslie was so clumsy by comparison.
Leslie was so clumsy by comparison.

The plant was harder to take care of than the tree because the 
OPTIONS:
- tree needed more attention.
- plant needed more attention.
plant needed more attention.

The trees have been growing worse in Matt's garden compared to the plants. That's because the 
OPTIONS:
- trees are sick.
- plants are sick.
trees are sick.