A volcanic bomb is a mass of molten rock bigger than 64 mm (2.5 inches) in diameter, formed when a volcano ejects viscous fragments of lava during an eruption. They also cool down into solid fragments before they land on the ground<span>.</span>
Answer:
The cell was first discovered by Robert Hooke in 1665 using a microscope.
The first cell theory is credited to the work of Theodor Schwann and Matthias Jakob Schleiden in the 1830s.
Hooke had discovered plant cells -- more precisely, what Hooke saw were the cell walls in cork tissue. In fact, it was Hooke who coined the term "cells": the boxlike cells of cork reminded him of the cells of a monastery.
