★ Biology Quiz
the walls of the xylem vessels are thickened by ……
A. subrin
B. cutin
C. lignin
D. cellulose
Select your answer:
Topics:
Cellular Components Urinalysis/ Immunology Make up Body System Interactions Hormones Common Diseases in Human Beings Physical Fitness Components Cell Theory and Microbiology DNA, RNA, Proteins Functional Anatomy in Track & Field Organization of Systems Genes and DNA The Blood Cardiovascular and Respiratory Circulatory & Respiratory Food MicrobiologyOther quiz:
Biology › ViewThe weak bond that holds one water molecule to another water molecule is called a ___.
A. polar bond
B. covalent bond
C. hydrogen bond
D. ionic bond
Meiosis and intro to Genetics › View
Which of the following alleles is homozygous (purebred) recessive?
A. Tt
B. tt
C. TT
D. t