If a single mutation turns off the growth of some pairs of legs within an organism, what's most likely affected?
a. a hox gene
b. a duplicated gene
c. a deleted gene
d. a substituted gene

its a hox gene

Ans.

In vertebrates, limb development is performed by a group of genes, known as Hox genes (homeotic box genes). These genes act as transcription factors and initiate the process of limb development in developing embryo. The Hox genes also play role in determination of head-to-tail axis of body plan.

A single mutation in Hox genes may results in formation of defective protein that turn off the growth of leg pairs in an organism. Thus, the correct answer is option A). 'a Hox gene.'

the correct answer is b

answer and explanation;

volcanic rocks are igneous rocks which form from lava, molten rock which has been thrust out of a volcano onto the surface of a rocky body such as an asteroid, planet, or dwarf planet.  

plutonic rocks are igneous rocks which form from subterranean chambers of molten rock or magma. plutonic rocks make up the base of continental crust as well as oceanic crust. their slow rate of formation causes them to be coarse grained since there is plenty of time for large crystals to form before the magma solidifies into rock.

the textural difference is that plutonic rocks are more coarse grained than volcanic rocks. plutonic rocks are coarse grained while volcanic are fine grained ; glassey or fragmental. since fine and coarse are adjectives the decision as to whether a rock is fine or coarse grained is generally made on the bases of whether or not the individual crystals can be seen in most if the rock.