Math 7 Grade 7

Can anyone please help me answer these math questions right away?

1. To determine what park visitors like, every tenth visitor is surveyed at the park entrance. Out of 180 visitors, 22% said they would like to have more walking paths. The park manager concludes that about one-fifth of all park visitors would like to have more walking paths.

Is this conclusion valid?

What type of survey is this?
simple random sample voluntary response sample convenience sample systematic random sample

2. Which type of data display would be best for showing how the height of a plant changes each week during a science experiment?

stem-and-leaf plot
bar graph
line graph
line plot