Correct answer: D
A pollen is where male gametes are produced and so the number of chromosomes, as we are talking about gametes, is n. This means that the grain of pollen will only have a copy of each gene, and therefore only one allele for each gene - one S, and one T or t. So, the possible combinations are ST and St.
Pericardium or pericardial sac.
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The answer is b
<span>1.Upper Epidermis – The upper surface of a leaf that protects the inner cells of the leaf. 2.Palisade Layer – Long, thin, tightly-packed cells where most photosynthesis takes place. 3. Spongy Layer – Loosely packed cells with many air spaces between them in order to allow carbon dioxide to pass among the cells and get to the chloroplasts. 4. Lower Epidermis – The bottom layer that protects the underside of the leaf and has many openings (stomata)</span>
Answer:B. Sunlight provides energy to producers
Explanation: photoautotrophs (plants) produce energy from sunlight by photosynthesis. This is the only energy production based on an external source of energy. Plants, whether alive or dead, are consumed by heterotrophs - bacteria, fungi and animals. The nutrients and energy from dead heterotrophs (and some live ones) are recycled by both autotrophs and heterotrophs.
1.) food
2.) water
3.) a habitat
