Scientists are concerned about the release of methane from the arctic because a. as a greenhouse gas methane is 20 times more potent than carbon dioxide b. the mass of the arctic’s methane is comparable to that of the earth’s coal beds c. global warming appears to be accelerating its release d. all of the above

d. all of the above

Methane is a powerful greenhouse gas that contributes to the phenomena of global warming. One mole of methane is 10 times more powerful than one mole of CO₂. It is a dominant greenhouse gas. In Artic region the methane is released from the sea bed and the permafrost soil.  The methane is released as natural gas reserve from these sources as a outcome of the process of methanogeneisis. It involves the partial or uncomplete degradation of dead remains of animals and plants and rapid heating and thawing conditions.

The gas releases in the atmosphere because of all the four options.

force is based upon mass and acceleration.the statement is not always true.

it can be explained from newton's second law of motion.

as per newton's second law of motion the rate of change of momentum is directly proportional to the applied force and takes place along the direction of force.

mathematically it can be written as -

                                              ⇒      

here   k is the proportionality constant whose value is 1.

                                                            [a is the acceleration=dv/dt]

hence we see that force not only depends on mass and acceleration but also on velocity and rate of change of mass. force f will depend on mass and acceleration only when mass is constant.

hence the statement that force is based upon mass and acceleration is false.