Question

which statement about a rock sample is an inference? 1 the rock scratches a glass plate. 2 the rock was formed 100 million years ago. 3 a balance indicates the rocks mass is 254 grams. 4 the rock has no visible crystals and is red.

Explanation:

An inference is a conclusion based on evidence and reasoning. The rock scratching a glass plate, its mass measurement, and its color and crystal - presence are direct observations. Determining that the rock was formed 100 million years ago requires analysis and interpretation of data (such as radiometric dating results), making it an inference.

Answer:

1. The rock was formed 100 million years ago.