A factory is a large industrial building where people or machines make things on a very large scale. Things like cars, toys and most common household goods are made in factories.
Harare is the capital of Zimbabwe. It has a population of around 2.8 million people.
You are hungry when you need to eat something. You usually get hungry when you have not eaten anything for some time.
Ivory is essentially teeth. Ivory usually refers to elephant's tusks, but any tooth large enough to be carved can be used as ivory. Before plastic was invented, ivory was commonly used for making ornaments, buttons, handles of knives and forks and the most familiar use - piano keys.
Today the trade in ivory is banned in most countries, and plastic or ivory substitutes are used where ivory was once used.