<h3>Answer:</h3>
<em>LETTER </em><em>C</em>
Explanation:
MAKE ME BRAINLIEST AND FOLLOW ME
67 million years ago in the form of phyollths (small sllica flecks in grass that make it difficult to digest)
Answer:
The respiratory centers that control your rate of breathing are in the brainstem or medulla. The nerve cells that live within these centers automatically send signals to the diaphragm and intercostal muscles to contract and relax at regular intervals.
Explanation:
In Earth’s history before the Industrial Revolution, Earth’s climate changed due to natural causes not related to human activity. Most often, global climate has changed because of variations in sunlight. Tiny wobbles in Earth’s orbit altered when and where sunlight falls on Earth’s surface. Variations in the Sun itself have alternately increased and decreased the amount of solar energy reaching Earth. Volcanic eruptions have generated particles that reflect sunlight, brightening the planet and cooling the climate. Volcanic activity has also, in the deep past, increased greenhouse gases over millions of years, contributing to episodes of global warming