definitions - set 8

Question 1

umbilical cord

Answer 1

an organ linking an embryo to the placenta, containing blood vessels

Question 2

unicellular

Answer 2

made of one cell

Question 3

urea

Answer 3

the main nitrogenous excretory product of mammals, produced in the liver from excess amino acids

Question 4

ureter

Answer 4

a tube that leads from a kidney to the bladder

Question 5

urethra

Answer 5

a tube that leads from the bladder to the outside

Question 6

urine

Answer 6

a solution of urea and other excretory products in water, produced by the kidneys

Question 7

uterus

Answer 7

the organ in a mammal in which the embryo develops

Question 8

vaccination

Answer 8

the introduction to the body of dead or weakened pathogens, to make a person immune to an infectious disease

Question 9

variation

Answer 9

differences between individuals of the same species

Question 10

vascular bundle

Answer 10

a vein in a plant, containing xylem vessels and phloem tubes

Question 11

vasoconstriction

Answer 11

narrowing of blood vessels

Question 12

vasodilation

Answer 12

widening of blood vessels

Question 13

vein

Answer 13

a blood vessel that carries blood towards the heart

Question 14

vesicle

Answer 14

a very small vacuole (space inside a cell)

Question 15

villus (plural: villi)

Answer 15

a tiny, finger-like process on the inner wall of the small intestine; villi increase the surface area for digestion and absorption

Question 16

vitamins

Answer 16

organic substances required in small quantities in the diet

Question 17

voluntary action

Answer 17

an action taken as the result of a conscious decision

Question 18

water potential

Answer 18

a measure of the tendency for water to move out of a solution; the more water in the solution, the greater its water potential

Question 19

xerophyte

Answer 19

a plant adapted to live in dry conditions

Question 20

xylem vessels

Answer 20

long hollow tubes made up of dead, empty cells with lignified walls, which transport water in plants and help to support them

Question 21

zygote

Answer 21

the diploid cell produced when two gametes fuse