<span>Although a star might look brighter than the Sun, a comparison of its absolute<span> magnitude might help prove that they have the same real brightness.
Absolute magnitude is a concept that compares the absolute brightness of celestial objects. The absolute magnitude of an object is defined as the apparent magnitude it would have if it were viewed at a standard distance of 10 parsecs (32.6 light-years) with no dimming of its light. The more luminous an object, the smaller the numerical value of its absolute magnitude.</span></span>
The right answer is vein (it contains blood and has valves).
The infra-cardiac veins of small and medium caliber possess this system of fight against gravity. The valves consist of a dense connective tissue, surmounted by endothelial cells, corresponding to a fold of the intima. They allow blood circulation in the sense organ / heart but prevent venous reflux.
Hi!
The correct option is B. Which genes are active.
Embryonic differentiation is a developmental process by which embryonic cells give rise to specialized cells and a diverse range of tissue structures. All of this unique cells essentially rise from a type of cells that are known as pluripotent cells.
But how do these pluripotent embryonic stem cells know which cells to differentiate into? This is where genes come into play. The cell has an inherent signalling ability that determines which gene is to be active and expressed. These specifically activated genes then translate into proteins for which it is specific, giving each cell, tissue and organ its particular identity.
Hope this helps!
