46. 1. combined to produce. 2. combining to produce 3. combining as a product of 4. combined for the production of
47. 1. of two different species 2. with different two species 3. for two species of difference 4. as the difference of two species
48. 1. also are intentionally produced 2. are produced intentionally also 3. can be also intentionally produced 4. can also be produced intentionally
49. 1. is of particular importance 2. looks particularly important 3. have importance particularly 4. are of importance particularly
50. 1. are usually larger and healthier 2. usually are larger and healthier 3. are larger and usually healthier 4. are larger usually and are healthier
51. 1. but more resistant than 2, and more resistant to 3. with more resistance than 4. despite more resistance to