To find out how many students are in the Environmental Club, you can calculate 10% of the total number of students in the seventh grade.
First, calculate 10% of 140:
\[ 10% = \frac{10}{100} = 0.10 \]
Then, multiply this by the total number of students:
\[ 0.10 \times 140 = 14 \]
So, there are 14 students in the Environmental Club.