In the datura plant, purple flower color is controlled by a dominant allele p. white flowers are found in plants homozygous for the recessive allele p. suppose that a purple-flowered datura plant with an unknown genotype is self-fertilized and that its progeny are 28 purple-flowered plants and 10 white-flowered plants.

part a

use the results of the self-fertilization to determine the genotype of the original purple-flowered plant.

a. pp
b. pp
c. pp

part b

if one of the purple-flowered progeny plants is selected at random and self-fertilized, what is the probability it will breed true?

a. 1/3
b. 1/4
c. 3/4
d. 2/3

Part A: Pp

Part B: 1/3

Explanation:

A: The purple flower color is regulated by dominant allele "P". Since self-fertilization of the purple-flowered plant with unknown genotype gives both purple and white-flowered progeny in almost 3:1 ratio, the parent plant was heterozygous dominant for the trait. Its genotype is "Pp".

Segregation of recessive and dominant alleles during gamete formation leads to the production of two types of gametes with either "P" or "p" alleles. The random fusion of these gametes produces progeny in following phenotype ratio= 3 purple: 1 white.

B. Out of the 3 purple-flowered progeny, 1 is homozygous dominant (PP). Therefore, the probability of the purple-flowered progeny to breed true is 1/3.  

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.

the answer is definitely a