Answer:
homologous structures
Explanation:
something like bat wings and human hands
they evolved from a common ancestor, but are now different and used differently
The palaeozoic started in a period in which invertebrates started proliferating rapidly and in large amounts, which was considered a historical event and the end of that gigantic era.
Hope it helped,
Happy homework/ study/ exam!
I believe the answer in the blank should be protostar
High-altitude environments present a number of physiological challenges for endothermic animals, as they are characterized by a lower partial pressure of oxygen (<span>) and lower ambient temperatures compared to low-altitude environments at similar latitudes. The reduced </span><span> at high altitude results in reduced oxygen loading in the lungs such that the blood may not carry a sufficient supply of oxygen to the cells of respiring tissues (</span>Bencowitz et al. 1982<span>; </span>Bouverot 1985<span>; </span>Turek et al. 1973<span>). This reduced level of tissue oxygenation can impose severe constraints on aerobic metabolism and may therefore influence an animal's food requirements, water requirements, the capacity for sustained locomotor activity, and the capacity for internal heat production.
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Oxygen is an electronic which can be defined as pure substance..we breath in oxygen and breath out carbon dioxide
