Which of these follows a cyclical pattern?
a. sunspot maxima and minima
b. condensation of a nebula
c. formation of a crater
d. formation of a black hole

Zoe is investigating the composition of substance a, an unknown substance. using chemical processes, she analyzes substance a and determines it is composed of sodium, oxygen, and hydrogen atoms in a ratio of 1 : 1 : 1. what is substance a? a. a compound b. an element c. a heterogeneous mixture d. a homogeneous mixture

In what way do investigations build scientific knowledge? the results of investigations lead to questions that cannot be tested. they reflect the opinions and social values of scientists, ensuring valid information. the results of investigations lead to new questions, which lead to new investigations. they are not influenced by the research of earlier scientists, so they are able to address gaps in understanding. i

How can liquids be seperated by density a the liquids are absorbed onto a paper b the liquids are turned into seperate vapors c the liquids are collected as they evaporate d the liquids are allowed to seperate into layers