<h2>540 million years ago
</h2>
Paleozoic.
Era immediately follows Precambrian It lasted about 4.5 billion years.
When did abundant fossil evidence first appear in the geologic record.
540 million years ago.
1. SI,
2. Number 10.
I'm pretty sure it's that, I just did something related to that.
Answer:
Without naturally occurring greenhouse gases, Earth's average temperaturewould be near 0°F (or-18°C) instead of the much warmer 59°F (15°C). The concentration of greenhouse gases, especially carbon dioxide and methane, has fluctuated naturallyover geological time scales.
Answer:
An ecosystem is biotic, not abiotic.
Explanation:
First, an ecosystem is a biological community of interacting organisms and their physical environment. Second biotic factors are nonliving things whereas biotic factors are living things in an ecosystem you have your producers or plants which then will be consumed by the primary consumers. With the primary consumers feeding the next group of consumers and then the next and then after they die they fertilize the ground allowing the producers to grow as it completes the circle of life.