Please help i need a jornal

If gases like carbon dioxide and methane make up less than 1% of the total atmosphere, why is it important for scientists to monitor changes in percentages of these gases?

To a of 4 x hz is 1. 0. mm nm nm

In which situation is the acceleration of a car negative? question 5 options: a)the velocity of a car was 75 km/hr over 4 hours. b)the velocity of a car reduced from 50 km/hr over one minute. c)the velocity of a car increased from 40 km.h to 75 km/h over 15 minutes. d)the velocity of a car was 45 km/hr at 2: 00pm and at 4: 00pm its velocity was 85 km/ht.