Matter is anything that has mass. everything has matter, even the air.
The Precambrian time refers to the time 4.5 billion to 542 millions year ago. This period is characterized by having reduced atmosphere and included reduced compounds. Scientists believed that atmosphere at that time was devoid of free oxygen and CO2 was present in excess. Before the complex life evolved on the Earth, the Precambrian Earth's ocean contained dissolved carbon dioxide.
"A. cutting down most of the trees in a forest to make furniture" is the correct answer because some trees play a vital role in processing the carbon in the air.
The distinguishing characteristics of the free living members of sarcodina are:
1. These are pseudopods (function in locomotion) which makes it the extentions of protoplasm.
2. These have both a clear ectoplasm and a granualated endoplasm.
3. These have nucleus both food vacuoles and contractile vacuoles.
The acetabulum is the cup-like structure where the femur articulates. The head of the femur is the specific structure which articulates in the acetabulum.
