There are multiple metric units to choose from! This tutorial goes through the process of choosing the best metric unit to use for measuring the mass of a given object.
The most common aphids on houseplants are the light green ones (pear aphids), but aphids can also be found colored pink, white, grey and black. Additionally, winged aphids can appear when colonies are established and fly to infect new plants. Juvenile aphids (nymphs) look like smaller versions of the adults.
The solid white cockatiels, with red eyes, are actually the lutino (the solid yellow/white body) and the white face (the lack of a cheek spot, and the lack of any yellow or orange pigment) mutations combined together, making the bird totally and completely white (with the red eyes of the lutino), If the bird is pure white with no color on the cheeks or crest but the eyes are dark and not red, then it is a Clear Pied (some call them Dark eyed Clear) it still is not an Albino