New cells generate from
(a) bacterial fermentation (b) regeneration of old cells
(c) pre-existing cells (d) abiotic materials

Explanation

To solve the question "New cells generate from," let's analyze the options step by step:

1. **Understanding the Question**: The question asks where new cells come from. This is fundamental in biology, particularly in cell theory.

2. **Reviewing the Options**:
- (a) **Bacterial fermentation**: This refers to a metabolic process where bacteria convert sugars into acids, gases, or alcohol. While bacteria reproduce, this option does not directly answer the question of how new cells are generated.
- (b) **Regeneration of old cells**: This suggests that old cells can regenerate into new cells. While some organisms can regenerate, this is not the primary mechanism for cell generation in all organisms.
- (c) **Pre-existing cells**: This option aligns with the cell theory, which states that all new cells arise from existing cells. This is a fundamental principle in biology.
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