If you mean molecular oxygen, O2, then no, there is no more than trace amounts on Mars (compared to the Earth which has an atmosphere composed of over 20% O2). Our atmosphere is mostly nitrogen (N2) followed by oxygen (O2) with smaller amounts of argon and carbon dioxide.
A ton is 2000 pounds (907.19 kg), so does it follow that a half-ton truck weighs 1000 pounds (453.5 kg)? Actually, the name doesn't refer to the weight of the truck. In fact, half-ton pickups weigh much more than that. The weight of a truck without cargo or passengers is called the curb weight. For example, many 2007 half-ton pickups have curb weights between 9000 (4082.3 kg) and 11000 (4989.5 kg) pounds [source: Edmunds].
1 Metric Ton = 2 204.62262 Pounds. For other units of weight conversion, please go to Weight Conversion. The tons to pounds conversion factors are listed below. To find out how many pounds in tons, multiply by the right conversion factor or use the converter below to convert from short tons. 1 Short Ton [US] = 2 000 Pounds. From pounds to tons conversion, please go to pounds to tons.