Which is an example of reflection?
two waves combining to form a larger wave
a wave bending as it passes through a narrow opening
an ocean wave bending as it approaches the shore
a wave bouncing off the side of a pool

d. a wave bouncing off the side of a pool

Explanation:

The example of reflection is wave bouncing off the sides of a pool. The simple meaning of reflection is it occur when the wave is hit by an obstacle and bounces  back into the same medium with same speed. It is property common to all the wave.

the answer is d

lies a supermassive black hole called sagittarius a*, or sgr a* for short.

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.