Capital Gain means the amount you receive after selling your capital assets such as property or shares. Capital gains need to report in your income tax return and pay tax on capital gains, this is a part of income tax which referred to a capital gain tax, it is not a separate tax. Capital gain is added to your income and it will eventually increase the tax you pay, you need to seek advice from your tax adviser on the amount of tax you will pay and keep aside the funds to cover the relevant amount. Capital gain tax is not applicable on depreciating assets such as business equipment and fitting on rental property. If you incurred a loss then you cannot claim it on other incomes but it will help to reduce the capital gain.
Foreign Income Tax Returns means that you need to pay tax on worldwide income if you are an Australian resident. So you have to declare income tax return on foreign income.
Foreign income includes business income which means you need to pay Australian tax return on all the foreign business activities depends on a number of factories in other countries.
Service income or employment is also included in a foreign income tax return which means that you need to declare tax for all the income i.e. salary, consultation fees or any other remuneration.