How are animals divided into groups based on the morphological trait of the number of tissue layers during development?

a.) two groups: those that have three tissue layers in their embryos and those that have two

b.) three groups: those that have four, three, or two tissue layers in their embryos

c.) three groups: those that have three, two, or one tissue layers in their embryos

d.) two groups: those that have two tissue layers in their embryos and those that have one

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Explanation:

sand 60

clay 10

silt 30

sandy loam should be dominated by the sand. as the amount of sand increased, the amount of slit needed to anchor the plants' roots to the sand will also be increased. even though the amount is very little, 10% part of clay is still necessary for proper oxidation.

step 1: nitrogen fixation- conversion of atmospheric no₂ into forms useful to plants by lightning, bacteria, and cyanobacteria.

step 2: nitrification-process of converting ammonia to nitrite or nitrate.

step 3: assimilation-plant roots absorb new form of nitrogen.

step 4: ammonification-conversion of organic nitrogen to ammonia by bacteria involved in decomposition.

step 5: denitrification-bacteria turns the decomposed matter back into n₂o, which is released into atmosphere; repeat cycle.