Questions

The presence of vitamin D in the body enhances the absorption of calcium by the intestine.

Secondary market refers to market where securities are traded after being initially offered to the public in the primary market and/or listed on the stock exchange.

The author of the book 'Panchashati Galpo' is Atin Bandyopadhyay or Atin Banerjee. He was a writer of Bengali literature.

The size of gear is usually specified by pitch circle diameter.

Osmosis is the process in which water molecules move from a region of higher water potential to a region of lower potential down a water potential gradient across a partially permeable membrane. It doen't requires any additional energy to do this work. 

So, Osmosis is a Passive.

Active and passive transport processes are two ways molecules and other materials move in and out of cells and cross intracellular membranes.

1. Active transport is the movement of molecules or ions against a concentration gradient (from an area of lower to higher concentration), which does not ordinarily occur, so enzymes and energy are required.

2. Passive transport is the movement of molecules or ions from an area of higher to lower concentration. Passive transport occurs because of the entropy of the system, so additional energy isn't required for it to occur.

3. Active transport requires energy to proceed, while passive transport does not require the input of extra energy to occur.