Question

which one of these would be considered an investigation? a measuring the ph of common household chemicals. b observing the effects of different track surfaces on the speed of a go - cart. c investigating the effects of different amounts of caffeine on heart rates of test subjects. d testing different amounts of fertilizer on tomato plants to find which causes the greatest growth.

Explanation:

All options involve scientific - style investigations. Measuring pH is a common scientific investigation in chemistry to understand the acidity or basicity of substances. Observing effects of track surfaces on go - cart speed is a physics - related investigation. Investigating effects of caffeine on heart rates is a biology/medicine - related study. Testing fertilizer amounts on tomato plant growth is an agriculture/biology - related experiment.

Answer:

A. Measuring the pH of common household chemicals, B. Observing the effects of different track surfaces on the speed of a go - cart, C. Investigating the effects of different amounts of caffeine on heart rates of test subjects, D. Testing different amounts of fertilizer on tomato plants to find which causes the greatest growth.