Answer:
a. heart development.
Explanation:
As the third week of fetal development starts, the process of formation of blood vessels begins. Also, the splanchnic mesoderm in the head end of the embryo forms heart on days 18 and 19. Since it develops heart, this part of the mesodermal cells is called the cardiogenic area. The underlying endoderm sends the induction signals to these mesodermal cells to form a pair of endocardial tubes that gradually develop into a single primitive heart tube. 
This primitive heart begins to beat by the end of the third week of development. Therefore, any drug that affects fetal development during the first 20 days of the pregnancy might affect the development of the heart.
 
        
             
        
        
        
I think the answer is the Eukaryote Kingdom. I hope this helps (:
 
        
             
        
        
        
Answer: The hilum is the point at which arteries carrying nutrients and lymphocytes enter the lymph node and veins leave it. Afferent lymphatic vessels enter the lymph node through the capsule peripherally and efferent lymphatic vessels leave the node via the hilum.
Explanation:
 
        
             
        
        
        
Recombination reshuffles alleles of two genes that lie on the same chromosome type, whereas independent assortment reshuffles alleles of two genes that lie on different chromosome types.
Explanation:
Alleles are two forms of same gene, they are located on the same loci of the homologous pair.
Recombination occurs when alleles from two homologous chromosomes get reshuffled during crossing over in meiosis.
Independent assortment refers to the tendency of alleles to be inherited independently from one generation to other.
 
        
             
        
        
        
Answer:
Accuracy and precision are alike only in the fact that they both refer to the quality of measurement, but they are very different indicators of measurement. Accuracy is the degree of closeness to true value. Precision is the degree to which an instrument or process will repeat the same value.