Platyhelminthes and nematoda lack a circulatory system and respiratory system. Match what each uses in place of these systems.

At a point in a body subjected to plane strain, the strains are εx = –190 με, εy = 630 με, and γxy = 330 μrad. Determine normal strain εn at the point for a counterclockwise coordinate rotation of 47°.

At a point subjected to plane stress on the surface of a structural-steel member, the stresses are σx = –90 MPa, σy = –100 MPa, and τxy = –40 MPa. Determine the diameter D of the corresponding in-plane Mohr’s circle.

True or False: Tribal leadership positions (e.g., “headmen” or “big men”) are an example of a formal office.

Write a Python function named count_long_words(words, min_length) that takes a list of strings and an integer. It should return the number of words whose length is greater than or equal to min_length. Do not ask for input inside the function. 

Gills in class Errantia are located ______________ while gills in class Sedentaria are located _______________.

Flame cells:

If a homogenous structural beam is completely free to expand or contract at both ends (unconstrained), raising its temperature uniformly will change its length but induce zero thermal stress.

What book do you recommend reading this summer?

Bearing stress is a type of localized normal compressive stress that occurs at the surface of contact between two separate interacting structural elements.