# sigmoid neuron vs Introductory Biology Tutor

The clearest difference is in-app purchases: sigmoid neuron at none against Introductory Biology Tutor's 1. On price, ads, device support and iOS requirement there is nothing between them.

Both are free to download. Introductory Biology Tutor sells 1 one-off in-app purchase. sigmoid neuron asks for nothing beyond the download.

## The numbers

| Metric | sigmoid neuron | Introductory Biology Tutor |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | — | Weekly |
| Size | 5 MB | 9 MB |
| Requires iOS | 17.6 | **17.0** |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Sungjun Kim](https://appshunter.io/developer/1602461985) | [David Soulsby](https://appshunter.io/developer/1776367161) |

## What reviewers say

### sigmoid neuron

[App page](https://appshunter.io/ios/app/sigmoid-neuron/id6740157799)

**Features:** macOS Compatibility

**In-app purchases:** none


### Introductory Biology Tutor

[App page](https://appshunter.io/ios/app/introductory-biology-tutor/id6814193597)

**Features:** Family Sharing, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Introductory Biology Tutor Access | $4.99 | one-time |


## Frequently asked questions

### Is sigmoid neuron free?

sigmoid neuron is free to download, with no in-app purchases.

### Is Introductory Biology Tutor free?

Introductory Biology Tutor is free to download, with in-app purchases available.

### Do sigmoid neuron or Introductory Biology Tutor have ads?

Neither sigmoid neuron nor Introductory Biology Tutor shows ads.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*