Following up on this question I asked some time ago, I am facing a similar scenario, but for the life of me I do not seem to get it right with the solution provided in the question above, and I have no clue...
The following is a MWE, all I want to do is to merge rows vertically (multirow), so that "Preventative impacts of RA" and its corresponding "G5 vehicle UVB 40h" span 4 rows, and "Preventative impacts of RP" and its corresponding "G5 vehicle UVB 40h" span 3 rows.
How should I do it? Many thanks!!
\documentclass[xcolor={dvipsnames,table}]{beamer}
%%TABLE
\usepackage{multirow}
\newcommand*{\arraycolor}[1]{\protect\leavevmode\color{#1}}
\newcolumntype{A}{>{\columncolor{red!20}}c}
\newcolumntype{B}{>{\columncolor{blue!20}}c}
\mode<presentation> {
\usetheme[compress]{Singapore}
\usecolortheme{orchid}
}
\begin{document}
\begin{frame}
\sffamily
\arrayrulecolor{white}
\arrayrulewidth=1pt
\renewcommand{\arraystretch}{1}
\rowcolors[\hline]{2}{.!50!White}{}
\resizebox{\linewidth}{!}{%
\begin{tabular}{A|B|A}
\rowcolor{.!50!Black}
\arraycolor{White}\bfseries {\footnotesize Question} & \arraycolor{White}\bfseries {\footnotesize A} & \arraycolor{White}\bfseries {\footnotesize B}\\
\bfseries {\scriptsize UVB impact on primary keratinocytes} & {\scriptsize G5 vehicle UVB 40h} & {\scriptsize G6 vehicle noUVB 40h}\\
\bfseries {\scriptsize Preventative impact of RA} & {\scriptsize G1 RA\_1nM UVB 40h} & {\scriptsize G5 vehicle UVB 40h}\\
& {\scriptsize G1 RA\_10nM UVB 40h} &\\
& {\scriptsize G1 RA\_100nM UVB 40h} &\\
& {\scriptsize G1 RA\_1$\mu$M UVB 40h} &\\
\bfseries {\scriptsize Preventative impacts of RP} & {\scriptsize G2 RP\_0.1$\mu$M UVB 40h} & {\scriptsize G5 vehicle UVB 40h}\\
& {\scriptsize G2 RP\_1$\mu$M UVB 40h} &\\
& {\scriptsize G2 RP\_10$\mu$M 40h} &\\
\end{tabular}
}%
\end{frame}
\end{document}


\resizeboxfor elements that contain text, you will end up with a suboptimal font size, see https://tex.stackexchange.com/questions/425453/why-not-scale-elements-that-contain-text for further information – samcarter_is_at_topanswers.xyz Nov 19 '18 at 09:25