Answer: D) By decreasing the activation energy of a reaction
A catalyst is a substance that speed up the rate of chemical reaction without affecting the product of the reaction. They only affect the rate of reaction not the yield of reaction.
Catalyst provide an alternative reaction pathway that has lower activation energy than that of uncatalysed reaction. It increases the frequency of collision and because of these greater collision which lowers the activation energy of the reaction.
This is called a joint. A place where two bones meet or come together is called a joint. The two bones are separated by cartilage to keep them from rubbing together.
Answer:
The answer is: After step 3, layers of sediment cover the dead organism.
Explanation:
Fossilization is the process by which living things are preserved as impressions on sedimentary rock (fossils). This is a rare process that occurs under the most appropriate conditions.
Process of Fossilization:
Permineralization is one of the most common types of fossilization. It involves the absorption of minerals into the remains, giving a detailed impression of the dead organism.
- The dead organism sink to the bottom of the ocean.
- The soft parts i.e. the tissue is decomposed whereas the hard parts of the body: the nails, bones and hair remain.
- The bones are gradually covered by sediments. The quality of the fossils often depends upon the type and quantity of sediment. River deltas have a large amount of sediment. This speeds up the process. Clay and mud sediments provide more detail to the fossil whereas sandy sediments render the details vague.
- Sedimentation is followed by permineralization. As layers of sediment accumulate over each other, the layers underneath turn to rock. This occurs due to the movement of minerals down to the seabed that harden the sediments. Minerals such as calcite may even replace the bones and other hard parts of the fossil, allowing it to remain preserved for long.
- The fossils discovered by archaeologists are present relatively closer to the surface of the Earth. This occurs due to the uplifting of rock layers due to the movement of the continental plates.
Cell membrane .
Photopigments
MItochondria
Nucleus
Contractile vacoule
Answer:
c. decrease rate of muscle activity
