What do animals use to get oxygen to every cell? lungs
red blood cells
osmosis
all of the above

how do animals obtain oxygen? animal cells exchange oxygen and carbon dioxide with their surroundings by diffusion across the puter coverings or membranes of cells.

Explanation:

The chemical inside them called Haemoglobin helps them do this. When the blood passes through a capillary next to an alveolus in the lungs oxygen diffuses into the red blood cells, where it combines with the haemoglobin to form a bright red substance called oxyhemoglobin.

Explanation:

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the level of progesterone is low at the pre-ovulatory phase of the cycle but it gradually increases and the levels are high at the luteal phase. if pregnancy occurs, the level of progesterone will be high throughout the pregnancy.

if egg is fertilized and the mother gets pregnant, progesterone starts preparing the uterus for the implantation. it starts building up the lining of uterus and make it hostile of the period of pregnancy.