Which statement is a scientific theory? A. Most cells are so small that they can be observed only through a
microscope.
B. The interactions between cells can be predicted with
mathematical equations.
O C. Cells are the fundamental units of all living organisms.
O D. The various functions of different types of cells can be determined
by experiments.

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.

be subject to a force andchange its motion

the duration of a photographic flash is related to an rc time constant, which is 0.100 μs for a certain camera.

truck y has a greater velocity than truck x.