Organelles is a possible answer.
If they were the same shapes and sizes then life would be exceedingly boring.
similarity
If they are the same shapes but differ only in size, then they are SIMILAR shapes. Otherwise, they are simply different shapes.
similar shapes are shapes that have the same angles but are different sizes.
They are said to be similar shapes and have the same interior angles.
No, they don't. There are over 200 different types of cells in a human body. All have different functions and different sizes and shapes. But, each type is of the same size in every human. For example, the muscle cells would be of the same size in all the humans. the red blood cells are different from the muscle cells in terms of their function and their size and shape; however, all human will have the same size of red blood cells. Hope that helped..
For the same reason that humans come in different colors, shapes, and sizes. All birds are unique.
No there different sizes and different shapes depinding on the make and model
No. They come in different sizes and different shapes, and have other differences as well.
Congruent
With cells, the rule of thumb is, structure defines function. Different cells throughout the body perform different functions. To perform these functions, they need different shapes. They all have the same DNA, but different "blueprints" are activated depending on where they are in the body.
This means that the different proportions are not the same. You could have different sizes or have the shapes change unproportionally.