Test of the Twins has 330 pages.
Time of the Twins has 421 pages.
War of the Twins has 411 pages.
The Daring Twins has 317 pages.
The Test - Animorphs - has 135 pages.
First Test has 240 pages.
The Psychopath Test has 240 pages.
The number of pages in the Aspire reading test can vary depending on the version and grade level of the test. Typically, the reading test is around 4-5 pages long.
Test of the Twins was created in 1986-08.
The ISBN for "Test of the Twins" by Margaret Weis and Tracy Hickman is 978-0-88038-352-7.
No there, is no specific blood test to check for twins, although higher than normal HCG levels in a blood test may be because of twins, although it is no where near accurate for predicting a twin pregnancy.
Assuming there's no question the babies are identical twins then, no. A paternity test on one will answer the question. However if they are fraternal twins (not identical) then, yes, each must be tested.
There is no such thing as "semi-identical" twins. If fraternal twins each take a paternity test, only the real father would show up as the father.