Answer:
D.) both a and c
Explanation:
Past observations made early in history as well as telescopes and space probes are very important in studying our universe and galaxies.
- Space probes are increasingly gaining momentum as technological and scientific advancements are being made.
- Telescopes are used to see or picture objects that are very far away in space.
- Also, understanding the past records and historical data is essential for the study of the universe.
Microscopes are not used in galactic studies. They are only used to study the world of micro-organisms.
A slide hammer puller. A slide hammer puller can be used to pulll a bearing from a bored hole that is pressed into. They are adjustable with either a collet or puller jaws. To remove the bearing, slide the weight back hard until it hits the flat area on the rear of the puller.
Answer:
luster, streak, hardness, cleavage, fracture, and crystal form are the most useful physical properties for identifying most minerals. Other properties-such as reaction with acid, magnetism, specific gravity, tenacity, taste, odor, feel, and presence of striations-are helpful in identifying certain minerals.
Answer:
Transmission electron microscope (MET): allows sample observation in ultra-thin sections. A TEM directs the electron beam towards the object to be increased. A part of the electrons bounce or are absorbed by the object and others pass through it forming an enlarged image of the specimen. To use a TEM, the sample must be cut into thin layers, not larger than a couple thousand thousands of angstroms. A photographic plate or a fluorescent screen is placed behind the object to record the enlarged image. Transmission electron microscopes can increase an object up to a million times.
A scanning electron microscope creates an enlarged image of the surface of an object. It is not necessary to cut the object into layers to observe it with an SEM, but it can be placed in the microscope with very few preparations. The SEM scans the image surface point by point, unlike the TEM, which examines a large part of the sample each time. Its operation is based on traversing the sample with a very concentrated beam of electrons, similar to the scanning of an electron beam on a television screen. The electrons in the beam can disperse from the sample or cause secondary electrons to appear. Lost and secondary electrons are collected and counted by an electronic device located on the sides of the specimen. Each point read from the sample corresponds to a pixel on a television monitor. The higher the number of electrons counted by the device, the greater the brightness of the pixel on the screen. As the electron beam sweeps the sample, the entire image of it is presented on the monitor. Scanning electron microscopes can enlarge objects 200,000 times or more. This type of microscope is very useful because, unlike TEM or optical microscopes, it produces realistic three-dimensional images of the object's surface.
A. Keeps carbon dioxide from escaping atmosphere
and slows diffusion
B. Prevents bicarbonate formation and slows
photosynthesis
C. Provides fossil fuels and recycles carbon dioxide
D. Prevents carbon dioxide from entering
atmosphere and dissolves fossil fuels
