Which of these substances are greenhouse gases? Check all that apply.
oxygen
carbon dioxide
helium
methane
nitrous oxide

Identify the type of energy used in each action. the flexing of an arm muscle: a signal transduction process by a neuron: a ball at the top of a hill: 1. electrical energy 2. mechanical energy 3. gravitational potential energy

The distant ancestors of tigers may have had bodies without stripes. use the theory of natural selection to explain how tigers may have evolved to have stripes.

Describe your dna model. which part do the straws represent? the pushpins? the paper clips and the black dots you made with the marker?