Is a disorder caused by the deficiency of one of the enzymes needed to convert the essential amino acid phenylalanine to the normally nonessential amino acid tyrosine; as a result, tyrosine cannot be made and becomes conditionally essential.

The table shows dates and appearance of index fossils. which rock layers can be dated most precisely? a) a layer containing both a fossil 4 and a fossil 3 b) a layer containing both a fossil 2 and a fossil 3 c) a layer containing both a fossil 1 and a fossil 4 d) a layer containing both a fossil 1 and a fossil 2

Agroup of plant cells was exposed to radiation, which damaged the chloroplasts and caused them to lose function. if the mitochondria were unharmed, what would happen to the overall function of the plant cells? a. the cells would not be able to make food, but would be able to release energy from biomolecules. b. the cells would not be able to replicate dna, but would be able to break down waste. c. the cells would not be able to break down waste, but would be able to replicate dna. d. the cells would not be able to release energy from biomolecules, but would be able to make food.

All annelids and arthropods have a blank body plan . unlike annelids, arthropods also have blank . the circulatory system of annelids is blank , while circulatory system of arthropods is blank .