Schleiden and schwann believed that
organisms are the basic unit of life
both cells and organisms are basic units of life
the questions of the basic unit of life are too abstract to answer
none of the above

The correct option is

None of the Above

Explanation:

Both of them have made their own innovations and achievements but collectively they have made one very important discovery (1839): "The Theory of Cells". This theory badges the cell as a basic particle of plants and animals. Schwann and Schleiden were capable to understand that some organism is unicellular, while others are multicellular. Additionally, they found out that the cell nucleus and the membrane refer to the properties of the cell, maintained by representations of various plant and animal tissues.

sex cells are usually half's then they find another half and make a fertilize egg