Figure 19 shows a diagram of a red blood cell from a turtle and a diagram of a red blood cell from a human - Edexcel - GCSE Biology - Question 8 - 2018 - Paper 1

To calculate the length of the magnified image:

$ext{Length of magnified image} = ext{Actual length} imes ext{magnification}$

Thus, $ext{Length of magnified image} = 20.5 ext{µm} imes 400 = 8200 ext{µm}$

Therefore, the length of the magnified image is 8200 µm.

First, convert 3.08 mm to micrometers:

$3.08 ext{ mm} = 3080 ext{ µm}$

Next, use the formula:

ext{Actual width} = rac{ ext{magnified width}}{ ext{magnification}}

Thus, ext{Actual width} = rac{3080 ext{ µm}}{400} = 7.7 ext{ µm}

In standard form, this is represented as: $7.7 imes 10^0 ext{ µm}$.

To measure the elasticity of the tissue:

1. Measure the initial length of the ring of tissue.
2. Gradually add weights using a mass carrier until the tissue stretches.
3. Measure the length after adding each weight.
4. Continue adding weights until the tissue no longer returns to its original length.
5. Record these lengths at each stage for analysis.

One safety precaution is to wear gloves to prevent contamination and protect yourself from exposure to potentially harmful substances.

The frog's circulatory system has only one ventricle and three chambers, whereas humans have two ventricles and four chambers. This setup in frogs allows for mixing of oxygenated and deoxygenated blood, resulting in less efficient oxygen transport to the tissues. In contrast, the human circulatory system effectively separates these two types of blood, ensuring more efficient oxygen delivery.