short term capital gains vs tax on business income

I have read tn taxtalk in Business line dt9/4/6. The question and answer given by columnist is given below.
question
I am retired and trade online. I average about one transaction a day. I don't trade in futures and options. I hold the shares on an average for 2-3 weeks. The primary motive of the investment is to earn profit. I have not employed anyone and carry out the transactions myself. I use a PC and a broadband Internet connection. The transactions are through a D-mat account and I pay the securities transaction tax on sale of shares. Will my gain be treated as capital gains or as business income? Easwaran
Answer
From the facts given by you, it appears that the gain should be treated as business income. One of the main factors that leads to this conclusion is the fact that you are making the investment with an intent to earn profit from the transactions of trading. An investor looks to the return from the investment and also holds some for fairly long periods, which may result in capital gains. Given that your intention is to earn profit from trading, the gain should be treated as business income. In such a case, the income after all expenses incurred for the purpose of the business — which will include the D-mat charges, the depreciation on the computer and the internet connection charges — will be taxed at the normal rates, applicable to an individual. You can claim from such tax a rebate under Section 88E. The rebate will be reduced from the tax and will be the lower of the tax on business income or the securities transaction tax paid. The tax on the business income will be computed by multiplying the average rate of income-tax with the business income. The average rate of income-tax will be the tax on total income divided by the total income and multiplied by 100.

from this, follows my queries:
1) what is the difference between gain and profit? Is there any definition of capital gains which negates this profit from trading being considred as short term Capital gain and taxed accordingly.
2)when Short term Capital gain isconsidered? In the above answer holding for fairly longer period and getting return is considered as capital gains. What si the "fairly longer period"? Is there any court cases exemplfies this and above?
3)Which one is beneficial to that investor?
4)What si rebate under Section 88E?
5) sentence "The rebate will be reduced from the tax and will be the lower of the tax on business income or the securities transaction tax paid" confuses me. Any clarfication?
6)How is income-tax with the business income calculated? Any claification with example will be more beneficial.