How is a fly different from a mosquito?

When it is alive we sing, when it is dead we clap our hands. What is it?

The dirtier I get, the whiter I look. Who am I?

Solve below rebus puzzle?

There was an aeroplane crash, every single person died, but two people survived. How is this possible?

I’m tall when I’m young, and I’m short when I’m old. What am I?

Use only one mathematical symbol and all numbers (0-9) to get a sum of 99

Two in a corner, one in a room, zero in a house, but one in a shelter. What is it?

Thomas has missed an excessive number of days of school, so he must meet with Principal Davis. Mr. Davis asks him "Why on Earth have you missed so many days?" Thomas replies "There just isn't enough time for school. I need 8 hours of sleep a day, which adds up to about 122 days a year. Weekends off is 104 days a year. Summer vacation is about 60 days. If I spend about an hour on each meal, that's 3 hours a day or 45 days a year. I need at least 2 hours of exercise and relaxation time each day to stay physically and mentally fit, adding another 30 days. Add all of that up and you get about 361 days. That only leaves 4 days for school." The principal knows Thomas is full of it, but can't figure out why. Where is Thomas going wrong?

what does the below rebus means?