Mechanical barriers provide a first line of defence against insect pests and pathogens, these mechanical barriers developed by plants;

COLUMN A	COLUMN B
A. Thorns	i) It can be found on the stem and petioles of roses and are formed by the epidermis
B. Spines	ii) Found on a lemon tree (Citrus sp.) are modified branches, as can be seen by their position in the axil of a leaf
C. Prickles	iii) Found on shoot and leaves of tomato (Solanum lycopersicum) are derived from epidermal cells
D. Trichomes	iv) which are characteristic of cacti (Opuntia spp.) in the New World, are modified leaves

Match correctly following combination of barrier developed by plants ;

#Question id: 4741

#Unit 8. Inheritance Biology

The F2 progeny from a particular cross exhibit a modified dihybrid ratio of 9 : 7 (instead of 9 : 3 : 3 : 1). What phenotypic ratio would be expected from a testcross of the F1?

#Question id: 4742

#Unit 8. Inheritance Biology

In birds, sex is determined by a ZW chromosome scheme. Males are ZZ and females are ZW. A recessive lethal allele that causes death of the embryo is sometimes present on the Z chromosome in pigeons. What would be the sex ratio in the offspring of a cross between a male that is heterozygous for the lethal allele and a normal female?

#Question id: 4743

#Unit 8. Inheritance Biology

Ectrodactyly is an autosomal dominant trait that causes missing middle fingers (lobster claw malformation). A grandfather and grandson both have ectrodactyly, but the intervening father has normal hands by x-ray. Which of the following terms applies to this family?

#Question id: 4744

#Unit 8. Inheritance Biology

Assume that long ear lobes in humans are an autosomal dominant trait that exhibits 50% penetrance. A person who is heterozygous for long ear lobes mates with a person who is homozygous for normal ear lobes. What is the probability that their first child will have long ear lobes.

#Question id: 4745

#Unit 8. Inheritance Biology

In some goats, the presence of horns is produced by an autosomal gene that is dominant in males and recessive in females. A horned female is crossed with a hornless male. The F1 offspring are intercrossed to produce the F2. What proportion of the F2 offspring will have horns?

#Question id: 4746

#Unit 8. Inheritance Biology

Two independent pure line varieties having deep red and brown phenotype in their seed coat were cross, the all f1 progeny is deep red. The F2 progeny obtain from selfing show deep red and brown in ratio of 15:1. Which of the following observation is correct?