If you are enabled for margin trading, you can easily get a margin balance by simply buying more shares than you have money deposited for, or withdrawing money from the account in amounts higher than your cash balance. Ameritrade just acts like you have the money in both circumstances and allows the transaction.
4. Mosquitoes vary in their size: they reach 1.6-12.5 mm (0.5 inch). Fossil mosquitoes were even 5 cm (2 inch) long. 5. Mosquitoes do not bite, they suck. 1,200,000 mosquitoes would be necessary to completely drain the average human of blood. Well, unless you die before, but of irritation. 6. An experiment in the Canadian tundra found that people who bared arms, legs and torsos reported approximately 9,000 bites per minute from swarming, newly hatched mosquitoes.
The short answer is yes. Mosquitoes do exhibit blood-sucking preferences, say the experts. One in 10 people are highly attractive to mosquitoes, reports Jerry Butler, PhD, professor emeritus at the University of Florida. But it's not dinner they're sucking out of you. Female mosquitoes -- males do not bite people -- need human blood to develop fertile eggs. And apparently, not just anyone's will do.