In protostomes, group of answer choices there is no body cavity. there is no ectoderm. the opening formed during gastrulation becomes the mouth. there is no endoderm. the opening formed during gastrulation becomes the anus.

The opening formed during gastrulation becomes the mouth.

Explanation:

Protostomes are the majority of animals classified as triblastics (which have three embryonic leaflets), except for the echinoderms and chordates.

The embryonic leaflets originated in the gastrulation of the triblastics (and consequently of the protostomes) are: endoderm, mesoderm and ectoderm.

In the process of gastrulation of the protostomes, the embryo has a cavity called the archenter (which will give rise to the intestine). The archenter communicates with the external environment through an opening, called blastopore.

In protostomes, the blastopore gives rise to the mouth, unlike deuterostomes, where the blastopore gives rise to the anus.

Given the above, it is concluded that the correct alternative is "the opening formed during gastrulation becomes the mouth".

answer: substrate concentration. enzymes work best when there is a high enough substrate concentration for the reaction they catalyse.

the nitrogen cycle provides nitrogen to the ecosystem from the atmosphere, ground and oceans. nitrogen is an important component of complex molecules such as amino acids and nucleotides, which lead to the creation of proteins and dna, the building blocks of all life. plants absorb nitrogen in the form of ammonium, nitrate ion and, on rare occasions, as amino acids. animals receive nitrogen necessary for biological processes from feeding on living or dead organic matter.