带数字的段落设置

Question

我希望所有段落都从同一个地方开始，但是当我添加数字时，它们似乎会移动。

以下是 MWE：

\documentclass[12pt,a4paper]{revtex4-1}
\usepackage{graphicx}% Include figure files
\usepackage{bm}% bold math
\usepackage[usenames]{color}
\usepackage[all]{xy}
\usepackage{amsmath}
\usepackage{fixmath}
\usepackage{natbib}
\usepackage{placeins}
\usepackage{verbatim}
\usepackage[top=0.59in,bottom=0.59in,left=0.59in,right=0.59in]{geometry}
%% packges not from aps
\usepackage{amssymb}
\usepackage{float}
\usepackage[nice]{nicefrac}
\usepackage{chemmacros}
\usepackage{hyperref}
\usepackage{xcolor}
\usepackage{multirow}
\usepackage{lipsum}
\hypersetup{
  colorlinks   = true,
  urlcolor     = red, 
  linkcolor    = black, 
  citecolor   = black 
}
\setlength{\parindent}{0pt}
\setlength{\abovecaptionskip}{0pt plus 0pt minus 0pt}

   \renewcommand\thesection{\arabic{section}}
    \renewcommand\thesubsection{\alph{subsection}}

\begin{document}
\newpage
\section{My section}

Exploring the sand with big tools.\\
\begin{figure}[htbp!] 
\centerline{
\includegraphics[scale=0.5]{sand.jpg}}
\caption{\footnotesize{picture of sand.}}
\label{fig:dis_3}
\end{figure} 
Testing our tools shows success.\\

\end{document}

Answer 1

\documentclass[12pt,a4paper]{revtex4-1}
\usepackage{graphicx}% Include figure files
\usepackage{bm}% bold math
\usepackage[usenames]{color}
\usepackage[all]{xy}
\usepackage{amsmath}
\usepackage{fixmath}
\usepackage{natbib}
\usepackage{placeins}
\usepackage{verbatim}
\usepackage[top=0.59in,bottom=0.59in,left=0.59in,right=0.59in]{geometry}
%% packges not from aps
\usepackage{amssymb}
\usepackage{float}
\usepackage[nice]{nicefrac}
\usepackage{chemmacros}
\usepackage{hyperref}
\usepackage{xcolor}
\usepackage{multirow}
\usepackage{lipsum}
\hypersetup{
  colorlinks   = true,
  urlcolor     = red, 
  linkcolor    = black, 
  citecolor   = black 
}
\setlength{\parindent}{0cm}
\setlength{\abovecaptionskip}{0pt plus 0pt minus 0pt}

\renewcommand\thesection{\arabic{section}}
\renewcommand\thesubsection{\alph{subsection}}

\begin{document}
\newpage
\section{My section}

Exploring the sand with big tools. \\ Testing our tools shows success.
\begin{figure}[htbp!] 
\centerline{
\noindent\includegraphics[height=5cm]{example-image-b}}
\caption{\footnotesize{picture of sand.}}
\label{fig:dis_3}
\end{figure} 

\end{document}