#Question id: 10699
#Unit 10. Ecological Principles
Two plant species co-occur in a prairie. Species X always occurs near species Y. However, species Y often occurs in isolation from species X and produces more seeds when alone than when growing next to species X. Which of the following interactions between species X and Y could generate this pattern?
#Question id: 5091
#Unit 5. Developmental Biology
In all vertebrate animals, development requires ________.
#Question id: 3413
#Unit 11. Evolution and Behavior
Following certain conditions is present in a population?
A- Large Population
B- Each locus carries two allele
C- Sexual selection
D- Frequency dependent selection
E- No linkage between genes
Which of the following above condition allowed to validity of Hardy- Weinberg Prediction?
#Question id: 28363
#Unit 5. Developmental Biology
Which of the following gene is responsible for the activation of the tips of the embryo and responsible for the specification of terminal axis?
#Question id: 12083
#Unit 10. Ecological Principles
In bottom sediments of lakes and streams, organic matter is broken down by heterotrophic microorganisms and ammonia is released. Under aerobic conditions, specialized bacteria convert ammonia to nitrate (nitrification). This nitrate, together with nitrate from other sources, diffuses into the deeper sediments, where it may undergo anaerobic conversion to nitrogen gas (denitrification). These sediments typically contain oligochaete worms that live with their heads buried and their tails waving back and forth in the overlying water. Plastic columns were packed with freshly collected stream sediments and then covered with layers of nitrate enriched water. A similar set of columns was packed with sediment that had been sterilized and then covered with either nitrate-enriched water or distilled water. Oligochaete worms were collected and acclimated to 20°(C)Following acclimation, worms were rinsed in distilled water and then added to three sediment columns. The columns were incubated in the dark at 20°C and monitored every three days for changes in the concentration of nitrate in the overlying water. Nitrate concentrations in each of the experimental treatments were plotted against time, as shown in the graph below
It can be concluded from the figure that