60 years is three half life for the substance, so 40*1/2^3=5
If a species is said to be extinct, then that species is reduced to zero. There are none living in existence. The affects to other organisms of its extinction would depend on their value to the ecosystem. Regardless, extinction completely stops evolution of the species extinct.
Temperate deciduous forests<span> or temperate broad-leaf</span>forests<span> are dominated by trees that lose their leaves each year. They are found in areas with warm, moist summers and mild winters. so </span>Precipitation in deciduous forests is best described as "<span>occurring throughout the years"</span>