<span>The protocell's fatty acid membrane allows chemical compounds, including the building blocks of DNA, to enter into the cell without the assistance of the protein channels and pumps required by today's highly developed cell membranes</span>
Autoregulatory neural and endocrine mechanisms activate after blood loss to compensate for the loss and restore homeostasis.
Neural mechanisms involve blood pressure and blood chemistry. Cardiac centers and vasomotor centers may increase the blood flow and cardiac output (sympathetic) or decrease the blood flow and cardiac output (parasympathetic). Peripheral vessels are also constricted and nor epinephrine decreases flow in the arteries and decreases the flow in the veins.
Endocrine control acts in the renal and adrenal organs, the brain and heart. RBCs, renin/angiotensiogen/aldosterone, catecholamines, antidiretic hormone, atrial natriuretic hormone regulate blood volume and blood pressure by keeping the fluids in the cardiovascular system. It also initiates vasoconstrictors or vasodilators.
One hypothesis that explains the result is : A) Two genes are involved with 12:3:1 epistasis, such that A_B_ and A_bb are black, aaB_ is brown,and aabb is green.
Explanation:
- This is a case of Dominant Epistasis.
- When two genes are involved and presence of dominant allele of one gene masks the effect of either allele of the second gene then the epistasis is termed as dominant epistasis.
- In the given case black :brown: green ratio is approximately equal to 12:3:1.
- Here presence of a dominant A allele that is responsible for the black colour masks the effect of either allele of B. Therefore A_B_ and A_bb produces black beetles
- Again , absence of dominant A allows B to express itself and Brown beetles are produced thus aaB_ is brown.
- When both the genes are present as recessive alleles, neither brown nor black colour is expressed and the beetles are green.Thus, aabb are green.
Carbon dating is a process that estimates the age of anything. However, there are flaws that exist. It may not be a precise number, but it does gives a good estimation.