How well do you understand living things and their vital processes? Whether you are preparing for JAMB, WAEC, NECO and Post-UTME, these Biology past questions and answers cover such subjects as the chemistry of life, botany, evolution, genetics, ecology etc to help you know what to expect, improve your speed and confidence and be really prepared for the actual aptitude test.
Radial vascular bundles are those in which
xylem is surrounded by phloem
phloem is surrounded by xylem
xylem and phloem occur on the same radius
xylem and phloem occur on the different radii
Correct answer is D
In angiosperms the vascular bundles are mainly of three types (i) radial (ii) conjoint (iii) concentric.
(i) Radial : Presence of radial vascular bundles is the characteristic feature of roots. Those vascular bundles in which xylem and phloem are present on different radii are known as radial vascular bundles. In between xylem and phloem bundles parenchymatous cells are present.
(ii) Conjoint : In these vascular bundles xylem and phloem are present on the same radii. Conjoint vascular bundles may be collateral (phloem is present only outer to xylem) or bicollateral (phloem is present on both sides of xylem). If cambium is present between xylem and phloem then the vascular bundle is known as open, otherwise it is called closed.
(iii) Concentric : Those vascular bundles in which one type of vascular tissue is surrounded by another type are known as concentric vascular bundles. These bundles may be amphivasal or leptocentric(phloem is completely surrounded by xylem) or amphicribal or hardocentric (xylem is completely surrounded by phloem). Amphivasal bundles are found in Dracaena and Yucca. Amphicribal bundles are found in stamens of many dicots etc.
Poison glands of snakes are homologous to
electric organs of fishes
stings of rays
sebaceous glands of mammals
salivary glands of vertebrates
Correct answer is D
No explanation has been provided for this answer.
Monotremes are unique mammals because they
posses hair
give birth to live young
secret milk in a pouch
lay eggs
Correct answer is D
No explanation has been provided for this answer.
transpiration
photosynthesis
absorption
None of these
Correct answer is A
No explanation has been provided for this answer.
10 gram of haemoglobin/100 gram of blood
14 gram of haemoglobin/100 gram of blood
18 gram of haemoglobin/100 gram of blood
24 gram of haemoglobin/100 gram of blood
Correct answer is B
No explanation has been provided for this answer.