It's C.
All chemical reactions will always need activation energy.
The best answer is b - it is rigid.
The cell wall is defined as the rigid, outermost layer found in plants and also certain bacteria, algae and fungi. It is absent in animal cells.
The plant cell wall is made up cellulose which is a structural carbohydrate. The cell wall is rigid and thus offers structural support allowing plant such as trees to grow to great heights.
It also helps prevent water loss, helps protect against insects and pathogens and keeps the shape of the plant.
Answer:
The field of view is widest on the lowest power objective. When you switch to a higher power, the field of view is closes in. You will see more of an object on low power.

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Microscope Notes
Answer:
The density of the liquid is 0.87 g/ml
Explanation:
Density = 17.4g divides 20ml = 0.87 g/ml (rounded to one significant figure)
