An organism that appears red with a black center on XLD agar is lactose-_____ and H2S-_____

a. positive; positive
b. positive; negative
c. negative; positive
d. negative; negative


C
A red colony with a black center on XLD agar indicates the presence of a lactose nonfermenter and an H2S-positive producer.

Biology & Microbiology

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Cryptic female choice is a type of intersexual selection where

A. the female genital tract selects for sperm that tend to be unrelated to the female. B. the egg itself has mechanisms to prevent fertilization by genetically related sperm. C. pollen from unrelated plants is not able to fertilize an egg. D. the female genital tract and/or the egg itself prevents fertilization by genetically related sperm. E. the female chooses which male can mate with her based on cryptic coloration.

Biology & Microbiology

Describe the colonial theory of animal origins

What will be an ideal response?

Biology & Microbiology

Four of the five choices listed below are monocots

Select the exception. a. grass b. lily c. melon d. orchid e. palm

Biology & Microbiology

Which of the following by-products of metabolism is the most toxic?

A) carbon monoxide B) ammonia C) urea D) lactic acid

Biology & Microbiology