Question

1. the most observable phenomena in the \solar cycle\ is the appearance of a) solar storms b) black holes c) solar eclipses d) sun spots

Explanation:

The solar cycle is marked by the periodic variation in the Sun's activity. Sun - spots are dark, cooler regions on the Sun's surface that vary in number over the solar cycle. Solar storms are related but not the most characteristic observable of the cycle. Black holes are not part of the solar cycle phenomena. Solar eclipses are a result of the relative positions of the Sun, Moon, and Earth and not related to the solar cycle.

Answer:

D. Sun spots