The SI unit would be grams, however considering a blade of grass is pretty small I would probably measure it in mg, milligrams.
That one!
Metric ruler
Centimetre
meter
liter
That one!
The period of a sound wave is the inverse of its frequency. To find the period, you can use the formula T = 1/f, where T is the period and f is the frequency. Thus, for a blade of grass vibrating at a frequency of 428 Hz, the period would be 1/428, which is approximately 0.0023 seconds.
Under a microscope, you would see the different plant cells that make up the grass tissue, such as the elongated cells of the blade, the tubular cells of the stem, and the root cells. You might also see chloroplasts, cell walls, and other cellular structures.
Metric ruler
You would use meters.
Kilogram
The gram.
The kilogram.
Millimeter
liter
Millimetres.
Grams.