Why is the scientific method described as nonlinear
a. the steps of the scientific method are repeated in a cycle.
b. scientists often repeat one or more steps several times.
c. sometimes scientists forget to perform some of the steps.
d. the steps can be performed only once but in any order.

b.Scientists often repeat one or more steps several times.

Explanation:

As you may already know, the scientific method is a set of steps followed by scientists that allows a phenomenon, or a situation to be observed and explained scientifically.

These steps follow a sequence, ranging from the observation of the phenomenon, the creation of hypotheses, experimentation, data collection, data interpretation and the creation of conclusions. However, it is common for scientists to have to repeat these steps countless times, until they have a complete conclusion about what is being observed. This is done to prevent experimental error and the dissemination of wrong results. For this reason, it is correct to say that the scientific method is not something linear, that it strictly follows a "recipe".

the second type of galaxy is called a barred spiral, which has a thing called a bar straddling the nucleus