Why should people care about invasive species?

Plz quick a natural resource that is replaceable through a cycle in nature or sustainable practice is called a? the subject is science

Which of the following statements is true about the relationship between genetic variation and natural selection? a. genetic variation must be present in a population before natural selection can act on it. b. genetic variation arises in a population as a result of natural selection. c. natural selection can act on a population whether there is genetic variation within the population or not. d. after natural selection acts on a population, the amount of genetic variation in the population always increases.

The big bang theory suggest that the universe is about - 300 million years old - 4.6 billion years old - 30 billion years old - 13 billion years old