yes, coral polyps are a keystone species. it would be a keystone species because it is important in order for the coral to thrive.
The flow of energy in an ecosystem is best described as energy moving in one direction from the sun to the producers then to the consumers.
Explanation;
Energy flow is the amount of energy that moves through successive trophic levels of a food chain in an ecosystem. Ecosystem maintain themselves by cycling energy and nutrients.
The energy from sunlight is taken up by producers which use it to produce organic compounds through photosynthesis. The energy is then passed successively to the trophic levels, that is from the producers to the consumers ( primary, secondary, tertiary and quotienary consumers). During this transfer some energy is lost at each trophic level in form of heat.
Directional selection favors one of the extreme phenotypes. Option B). Fewer plants with thin seed coats will be able to germinate, leading to a higher proportion of plants that produce seeds with thick seed coats.
<h3>What is directional selection?</h3>
Directional selection increases in the proportion of individuals with an extreme phenotypic trait.
There must be a selective pressure or environmental pressure acting on populations to lead the species to increase the number of individuals expressing that extreme phenotype.
This selection presents more frequently in those cases in which interactions between living organisms and the environment modify in the same direction.
In the exposed example the environmental pressure is drought during several years.
Drought periods decreases the fitness of plants that produce thin seed coats because they dehydrate before germinating.
Originally the population expressed both types of seeds. But after the drought pressure, only plants that produce seeds with thicker coats got to survive and reproduce.
The correct option is B). Fewer plants with thin seed coats will be able to germinate, leading to a higher proportion of plants that produce seeds with thick seed coats.
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B. plastic packing
A and D are biological hazards and C is a chemical hazard
