Hydrogen atoms are compressed
together by the enormous gravitational force
of the sun, causing them to fuse int a helium atom (which is heavier than
hydrogen), subatomic particles and enormous
release of atomic energy. The attached
picture shows the sequence of the main reaction
at the core of the sun.
Answer:
The correct answer is A.
Explanation:
A mutagen changes the level of mutations that occur in the DNA either by affecting it physically or chemically. This helps researchers create different organisms with altered phenotypes according to what the research needs so that the genes can be investigated further under a controlled environment.
So the answer is A.
I hope this helps.
The correct answer is E. Vertebrates are all related to a common ancestor
Explanation:
According to biology and evolution, organisms from different species but that share similarities in morphology (body structures) as well as in genetics often have a phylogenetic relationship which means they descend from the same organism or share a common ancestor. This applies to multiple taxonomical levels including classes such as mammals or birds as it has been proved each of this derived from a common ancestor. Therefore, the similarity in the body structure (morphology) in all mammals suggest vertebrates are related to a common ancestor and as they evolved from this, they share similarities not only in terms of morphology but also in genetics.
Answer:
The correct option is A. Steroid hormones exert their action by entering the nucleus of a cell and initiating or altering the expression of a gene.
Explanation:
Steroid hormones are derived from cholesterol and regulate multiple biological processes. All steroid hormones exert their action by crossing the plasma membrane and by binding with their respective intracellular receptors. They stimulate cell growth in a very different way, their lipophilic nature gives them the ability to cross lipid barriers, so, without the need for extracellular signals, these hormones can easily enter the cell, cross the cytoplasm and reach the nucleus. There they bind to specific receptors that are associated with DNA promoter regions, modifying their structure and promoting the expression of the genes under their control.
No. The trends go in different directions. CO2 goes up more than the volcanoes. It is the general trend that makes a difference compared to the fluctuations.
