Something is abject if it is utterly hopeless and miserable, of the worst order. For example, abject poverty.
A defect is something wrong with something, that stops it from being perfect. A defect in a machine might stop it from working at all. A defect might also be called a flaw or imperfection.
Something is flecked if it has small spots of another color through it. Many different kinds of stone are flecked, and the iris of many people's eyes are flecked.
Injecting is a way of forcing a liquid inside something else. Medicines are often injected into people's vein using a syringe. The person in the picture is injecting marinade under the skin of a chicken before cooking it.
Insects are a very common group of creatures, found all over the world except the sea. Insects all have six legs and antennae on their heads to help them find their way around. Many insects have wings. Insects lay eggs and many start life as a worm-shaped larval stage before growing up into the adult form that you see everywhere. The larval stage of the butterfly, the caterpillar, is the most well-known.
Something that is free of flaws and imperfections and cannot be made better in any way is perfect.
Something reflects light if it is shiny enough that the light hits it and bounces back off it. The man in the picture has sunglasses that reflect light.