Answer:
Gabbro and basalt
Explanation:
The oceanic crust is mainly made of gabbro rocks and different types of basalt rocks.
Answer:
4 billion years
Explanation:
Scientists have found the oldest known rocks on Earth. They are 4.28 billion years old, making them 250 million years more ancient than any previously discovered rocks. Earth formed about 4.6 billion years ago from a disk of gas and dust circling the sun.
Schist has the highest metamorphic grade.
Answer:
305 days
Explanation:
Lactation is ideally 305 days, but in practice it is usually more, followed by a two-month dry period prior to the next calving. A cow's milk yield is influenced by many factors, which are described in more detail in, Efficient Milking.
