The meter is the foundational unit for measuring length in the metric system. It is standardized and widely accepted among scientists and educators.

A ruler is designed specifically for measuring lengths, making it ideal for measuring small objects like a pencil. The other instruments are used for measuring temperature, weight, or air pressure.

The gram is the standard unit for mass in the metric system, particularly useful for measuring small objects. Other units listed are used for length, volume, and time respectively.

A thermometer is specifically designed to measure temperature by detecting changes in thermal energy. The other instruments measure different properties such as length, weight, or time.

A liter is the common unit used for measuring the volume of liquids in the metric system. It provides a standardized measure, unlike meters, grams, or seconds which are used for length, mass, and time respectively.

One meter is equivalent to 100 centimeters, which is a foundational conversion in the metric system. This conversion is essential for accurately measuring and comparing lengths.

A flexible measuring tape is designed to bend around curves, making it ideal for measuring the circumference of circular objects. The other tools are not suitable for curved measurements.

Since there are 1000 milliliters in one liter, dividing 2500 by 1000 gives 2.5 liters. This conversion is a basic application of metric unit relationships.

A digital kitchen scale provides precise measurements for ingredients, making it ideal for verifying 500 grams of flour. The other tools are designed for measuring length or temperature.

The correct order from smallest to largest in the metric system is millimeter, centimeter, meter, and kilometer. This order reflects the standard progression of unit size in metric measurements.

The error due to the smallest division an instrument can measure is known as the least count error. It reflects the limitations of the instrument's precision.

Since there are 1000 milliliters in a liter, multiplying 3 by 1000 results in 3000 milliliters. This conversion factor is critical when working with metric units of volume.

Distance is the measure that quantifies how far an individual has traveled, making it the relevant measurement for a running race. The other options pertain to different physical properties such as volume, mass, or temperature.

The liter is the standard unit for measuring liquid capacity and is the most appropriate for items like water bottles. Other units measure different physical quantities such as length or mass.

A protractor is designed specifically for measuring angles in geometric figures. The other instruments are used for measuring lengths or drawing circles.

The perimeter of a rectangle is calculated by adding the length and width and then multiplying by two. In this case, (12 + 7) x 2 equals 38 meters.

The absolute error is typically taken as the instrument's least count, which is 0.01 meter in this case. This reflects the smallest measurable increment, thereby representing the uncertainty in the measurement.

One cubic meter is equivalent to 1000 liters, so 2.5 cubic meters equal 2500 liters. This conversion is crucial when moving between units of volume in different scales.

The car's average speed in km/h is 75 km/h, since 150 km divided by 2 hours equals 75 km/h. Converting 75 km/h to m/s using the factor 1 km/h ≈ 0.2778 m/s results in approximately 20.8 m/s.

Converting all measurements to the same unit prevents errors and inconsistencies when combining data. This uniformity is vital for achieving accurate and reliable results in experiments.