In what main way did steam-powered warships and merchant ships affect empire building in the 1800s

A warship or military ship is a ship conceived and built for military or war functions.

Warships are usually constructed totally differently from merchant ships or tourist vessels. They have weapons systems, are prepared to take damage and are usually faster and more maneuverable than these. Unlike merchant ships, warships only carry weapons systems, ammunition and supplies for their crew. Warships normally belong to the navy of your country, although there have been times, in the past, that were operated by individuals or private companies.

In times of war the difference between a warship and a merchant is often confusing. In war, often, the merchant ships have been armed and used as auxiliary ships, as happened with the Q-ships in the First World War and with the armed merchants in the Second World War. Until the seventeenth century it was common for merchant ships to be forced into naval service and it was not uncommon for up to half of the ships in a fleet to be merchant ships. Until the danger of piracy ended in the nineteenth century, it was common to arm large merchant ships such as galleons.

Both types of boats were fundamental in the struggle for the domination of the sea and for obtaining the hegemony of them. These helped the creation and development of contemporary empires.

it's not the readmission

the fact that could also be added to column b is that during world war ii, specifically between the years 1941 and 1945, japan expanded its territory towards the indonesian territory in what was known later as part of the "pacific war". in that time, japan could conquer the philipines, singapore,   borneo, central java, malang, cebu, sumatra and various other islands of the area, therefore expanding its territory for a brief period of time.