I had the same question. After a little research, I'm pretty sure they are "bloodworms", which sound horrible but are actually harmless. They are midge larvae (midge are small flies).
See also this web page:
http://www.naturegrid.org.uk/biodiversity/invert/midges.html
A plane figure.
At a scale of 1.8 to 1, the corresponding length on the smaller figure is 6 2/3 cm (6.66 cm) 12 cm is approximately 1.8 times 6.66 cm
no.
scale factor
The widest part of Russia is approximately 5,000 miles in length. The total length of Russia's borders is approximately 37,860 miles.
A 3D figure shows length, width and depth. While a 2D figure only shows length and width.
All solid figures have length, width and height and, conversely, if a figure has length, width and height then it is a solid figure.
The length, width, or height of a solid figure is measured in units of length. The area of the figure's outside surfaces is measured in squared units of length. The volume of space filled by the figure is measured in cubed units of length. The mass of the figure is measured in units of mass. The weight of the object is measured in units of force. The age of the figure is measured in units of time. etc.
Nile - approximately 4,132 miles long Congo - approximately 2,922 miles long
a solid figure
It is the side of an isolateral figure.
An equilateral figure means that the figure has all sides that are the same length.