Regional specialization of the digestive tract is associated with an incomplete digestive tract.

Enter your answer to the following in the space below. Provide the rational for why cephalization is associated with directional movement. Limit answer to 1 or 2 sentences.

The respiratory membrane includes

Fetal hemoglobin has a __________ affinity for oxygen than adult hemoglobin

The chloride shift occurs in exchange for

One day Estela received a very good surprise from her boyfriend, Tomás. Complete the paragraph with the correct form of each verb in the preterite or imperfect to find out what happened. For your reference: á é í ó ú ü ñ // Á É Í Ñ Ó Ú Ü // ¿ ? // ¡ !         Estela (1) [word1] leyendo un libro cuando Tomás la (2) [word2] por teléfono. Tomás la (3) [word3] a ir a un restaurante esa noche. Estela (4) [word4] mucha tarea que hacer, pero (5) [word5] la invitación de Tomás.       Tomás (6) [word6] a las ocho y ellos (7) [word7]. (8) [word8] buen tiempo y ellos (9) [word9] caminar al restaurante. Mientras (10) [word10] por la calle, se (11) [word11] cariñosamente. Entonces, Tomás (12) [word12] un regalo pequeño de su chaqueta y se lo (13) [word13] a Estela. Estela (14) [word14] el regalo rápidamente. (15) [word15] un reloj. La semana pasada Estela (16) [word16] su reloj y por eso (17) [word17] un reloj nuevo.       Estela le (18) [word18]: “¡Muchas gracias”! a Tomás y ellos se (19) [word19] y se (20) [word20] allí en la calle. Entonces, (21) [word21] al restaurante y (22) [word22] una cena excelente.

Type I alveolar cells

The total pressure is the sum of the individual partial pressures of the gases in the mixture.

If unable to see this image, use this link. Observe the highly highly branched structure of a platyhelminth that is shown stained black in the image above. This structure secretes digestive enzymes, is the location of chemical digestion, and distributes digested nutrients to all parts of the body.  What structure is this?

The largest gas component in the atmosphere is