You can design such dialog boxes using the following website.
https://carbon.now.sh
First learn basic HTML, then CSS and responsive CSS for Static websites and thereafter JavaScript and PHP for dynamic pages. If you also want to learn jQuery for more better works learn it at the same time with JavaScript
Yes, a vector which has zero magnitude is also a vector in case of two vectors travelling in opposite directions with equal magnitudes. At this case, the resultant vector has zero magnitude but it is still a vector. We call it a null vector.
The Rh factor(the Rhesus factor or Rh antigen), is a protein that can be found on the surface of red blood cells. It is one of the most important blood group systems in human blood typing. The presence or absence of the Rh factor is denoted as either Rh-positive (+) or Rh-negative (-).
