The earth, the sun, and the rest of the solar system are almost unimaginably old when viewed on a human time scale. while modern humans first evolved approximately 200,000  years ago, the age of the earth, the sun, and the rest of the solar system is approximately  years.

The health, management and conservation of biodiversity, is a challenge facing ecosystems worldwide. the major factors that affect the health and function of the great barrier reef are climate change and pollution. which question investigates the effects of a biotic factor on the reef ecosystem?

The cluster of developing cells from conception until birth is called an

2. cheryl hears a new song on the radio every day during the week on her commute to work. surprisingly, when the song comes on at a party on saturday night, she knows most of the words without trying. describe the three ways that we use cognition to learn without reinforcement. which type of cognitive learning without reinforcement best explains how cheryl knew the song lyrics? explain your answer.