It takes about 2000 gallons of water to grow a pound of almonds. During the drought in California, much more water was pumped out of the ground in the central valley to irrigate crops. This reduces the water table, so the remaining water has to be pumped farther. In a year with little rain, the water table can drop by many feet, and in some places the water level is hundreds of feet below where it used to be. Many of the water pumps use gasoline motors. If you are an almond farmer, calculate how much gasoline per pound of almonds you will need to use to provide the energy required to pump water up the 100 feet the water table could drop in a bad drought.

c)as speed changes, wavelength and frequency change.

everything changes!

answer: the correct answer is 1.

explanation: there are various process in which a radioactive nuclei decays:

1) alpha decay: in this process, a heavier nuclei decays into lighter nuclei by releasing alpha particle. the mass number is reduced by 4 units.

2) electron capture: in this decay process, a parent nuclei absorbs an electron and gets converted into a neutron. simply, a proton and an electron combines together to form a neutron. mass number does not change in this process.

3) gamma ray emission: it is a decay process in which an unstable nuclei gives excess energy by a spontaneous electromagnetic process. this decay releases . this process does not change the mass number.

4) positron emission: it is a type of decay process, in which a proton gets converted to neutron and an electron neutrino. this is also known as -decay. in this the mass number remains same.

from the above information, we see that only alpha-decay is producing a change in the mass number of the nucleus.