Explanation:
The Earth's geologic past is divided into hierarchical time periods. This hierarchy comprises eons, eras, times, epochs, and ages, from largest to smallest. The Cenozoic, Mesozoic, and Paleozoic Periods are the three main divisions of the Phanerozoic.
Biodiversity decreases, and the overall health of the ecosystem decreases.
Answer: Option D
<u>Explanation:</u>
In a niche when two different species occupy a niche competition arises between them. In due course both the species fight for existence and nature selects the best adaptable one to win. The other species either reduces in its population or gradually in struggle for existence they deteriorate and die.
Hence a decrease in bio diversity happens here due to natural selection. If the biodiversity is decreased in a particular niche it affects the growth of different species which in turn affect the whole ecosystem resulting in decrease of the overall health in an ecosystem.
Answer:
Antibiotic resistance can evolved in bacterial population in the following ways:
Explanation:
- In response to constant exposure to antibiotics some members of a bacterial population develop some beneficial mutations in some essential genes that gives them survival advantage in terms of food and space over the sensitive bacterial strains and hence they are capable of out-competing the sensitive bacteria.
- This happens due to the process of Natural Selection.
- These genes are called antibiotic resistance genes and bacteria usually carry them on plasmids in form of cassettes where genes resistant to multiple drugs are incorporated. These plasmids are called the MDR or Multi-Drug Resistance Plasmids.
- These resistant plasmids can be easily transferred among bacterial populations by conjugation, transformation or transduction or direct plasmid transfer.
- The resistant genes encode for proteins that render the drug ineffective by promoting their efflux from the cells, preventing their entry into the cell, chemically modifying them such that they become non-functional or altering the target site of the drug.
Answer:
the answer is C
Explanation:
this shows how nutrients in the body because it enters the blood capillary which therefore goes through the small intestine.
I really hope this is helpful and understanding.