apache using high memory

I have an instance of virtualmin install on a dedicated box.

Recently I've seen apache, or at least my conclusion came to apache consuming lots of RAM. When all is fine I have ram going at 22%, but after a while as in a couple of days or more when I log back into virtualmin it says that my RAM is at 85%!

When I click on memory to view processes I see something similar to the below. I configured mysql to be highly available so I get that one. But I do not understand apache. Is it because it spawns every time there is a connection made to one of the sites? if so, why is it spawning with such a high memory rate of 572.56mb?

if I do systemctl restart httpd my RAM goes right back down to 22% and will slowly cimb back up.

730 mysql 1.79 GB /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid
10283 root 717.94 MB /usr/sbin/rsyslogd -n
19508 apache 573.34 MB /usr/sbin/httpd -DFOREGROUND
19509 apache 573.27 MB /usr/sbin/httpd -DFOREGROUND
21468 apache 573.01 MB /usr/sbin/httpd -DFOREGROUND
19507 apache 572.96 MB /usr/sbin/httpd -DFOREGROUND
21594 apache 572.95 MB /usr/sbin/httpd -DFOREGROUND
19506 apache 572.93 MB /usr/sbin/httpd -DFOREGROUND
25345 apache 572.82 MB /usr/sbin/httpd -DFOREGROUND
1132 apache 572.79 MB /usr/sbin/httpd -DFOREGROUND
1133 apache 572.56 MB /usr/sbin/httpd -DFOREGROUND
1134 apache 572.56 MB /usr/sbin/httpd -DFOREGROUND
19502 root 572.29 MB /usr/sbin/httpd -DFOREGROUND