The alula is a small structure that is found on birds. It is located at the joint between the hand wing and the arm wings of birds and it is the freely moving, first digit of a bird's wing. It is normally used by birds in slow flight. In humans, the structure that is comparable to the alula is the thumb.
The procedure by which the female gametes or ova are produced is known as oogenesis. The female gamete is known as an ovum. The process of oogenesis begins in the embryonic stage, the development of ovum takes place from the primary oocyte by maturation.
Each of the primary oocytes goes through the process of meiosis to generate one ovum. Thus, two primary oocytes will produce two ova after going through meiosis.
Answer:
(B) Energy transfer between trophic levels is almost always less than 20% efficient.
Explanation:
The ultimate source of energy on the Earth is the Sun. The energy coming from the Sun is captured by green plants by the photosynthesis. During photosynthesis sun energy is fixed into chemical energy (carbohydrate). So, in an ecosystem energy flow is unidirectional (from sun to the green plants). The fixed chemical energy from green plants is transferred to the herbivores then to carnivores through food. When one organism eats another organisms, only 10 % of the energy present in the organism is transferred as a food for the next organism and a large amount of energy is lost as heat into the environment. Thus, energy keeps on decreasing when stored energy moves from producers to top consumers. Thus, less than 20% energy transfer limits the trophic levels in most of the ecosystem.
Light positioning include;
1. Extrinsic muscles.
2. Pupil.
3. Accommodation.
4. Cornea
5. Ciliar bodies.
Sensory processing include;
1.Photoreceptor.
2. Occipital cortex.
3. Bipolar cells.
4. Ganglion cells.
5. Amacrine cells.
One of the main functions lipids do is storing energy. If a person eats excessive amount of food, lipids help store the energy in the form of fat molecules in the body to use later.
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