Answer:
Elements and compounds cannot be broken down into simpler substances by an ordinary process because of the following reasons.
1) Elements cannot be broken down by chemical or physical methods because elements is composed of atoms which are indivisible.
2) Compound cannot be broken down into simpler substances by ordinary process because elements present in the compound are combined with each other chemically.
An oil spill from a tanker is an example of point-source pollution.
Answer:
The answer is C. The cell took in another ancient prokaryotic cell, which began living inside it.
Explanation:
- The Endosymbiont Theory explains the evolution of membrane bound organelles such as mitochondria and chloroplasts.
- According to the theory, mitochondria evolved when an ameoba like organism engulfed bacteria capable of cellular respiration.
- Similarly, chloroplasts were developed when the ameoba like organism engulfed cyanobacteria or blue-green algae capable of photosynthesis.
- These organisms survived inside the ameoba over millions of years to develop into mitochondria and chloroplasts.
- The fact that mitochondria and chloroplasts have their own circular DNA and ribosomes is evidence of the endosymbiont theory.
The correct answer is "Phylum Urochordata: xi = 25; yi = 77".
The table presented in this exercise can be used as a tool to examine any connection between the microRNA (miRNA) diversity and the morphological complexity in a phylum. The Xi column represents the average number of miRNAs in a phylum, while the Yi column represents the average number of cell types in that phylum. The eight observation of this table refers to the data obtained from the phylum Urochordata.
MicroRNAs are small non-coding RNAs which regulate gene expression post-transcriptionally. They are used as phylogenetic markers as they have a very low rate of evolution. Also, they are very useful because it has been shown that phyla with very high levels of morphological innovation have high numbers of miRNA concentration.
Answer:
Option A. amphipathic molecules
Explanation:
Amphipathic molecules have both polar and non-polar parts which means they contain hydrophilic and hydrophobic regions in their structure.
These molecules are found in lipids. More specifically, phospholipids are considered as the fundamental building block of the cell membrane. They are arranged in a bi-layer having a hydrophilic head and hydrophobic tails to maintain the fluidity of the membrane.
