UNAM
A continuación, se presentan elementos químicos con su número atómico entre paréntesis.
argón (18) calcio (20)
potasio (19) niquel (28)
Exani II, Exani II -> Estructura de la Lengua
La frase: "La Sra. Ramírez siempre nos ve por encima del hombro", significa que...
GEOGRAFÍA SIMULADOR PARA LA UNAM
La globalización está asociada con el desarrollo de comercio internacional, controla en más de un cincuenta por ciento por
Examen Simulacro UAM
El choque de la Placa de Cocos y la Norteamericana produce sismos que afectan principalmente a:
Inglés
Choose the correct answer for each question according to the information in the text. Each line is numbered to help you identify them quickly.
| Sunflowers Make Bees Poop—a Lot. Here's Why That's Good | |
|---|---|
| Paragraph | Text |
| [1] | Bumblebees and other pollinators face many threats, including pesticide exposure, |
| [2] | climate change, habitat loss due to agriculture and development, and pathogens |
| [3] | that ravage multiple species. But a recent finding may help lighten their load. |
| [4] | Previous studies have shown sunflower pollen can work like a medicine for |
| [5] | bumblebees afflicted by a parasite called Crithidia bombi, a single-celled organism |
| [6] | that takes up residence in the bee's gut [and harms their health]. But scientists couldn't |
| [7] | explain how sunflower pollen vanquished C. bombi—did it boost the bees' immune |
| [8] | function, or perhaps poison the parasite directly? |
| [9] | New research, published in the Journal of Insect Physiology, shows the answer is |
| [10] | deceptively simple. "Sunflower pollen makes bumblebees poo a whole lot," says lead |
| [11] | author Jonathan Giacomini, which flushes the parasite out. |
| [12] | Plant products like nectar and pollen are a treasure trove of potential insect medicines |
| [13] | that scientists are just beginning to understand, he adds. "There are natural things out |
| [14] | there that bees are interacting with that can be beneficial for them," Giacomini says. |
| [15] | And by making changes to the landscape, scientists hope we can help give bees a |
| [16] | fighting chance. |
| [17] | Plant power |
| [18] | If you happen upon a fuzzy, buzzing, flying creature in eastern North America, there's |
| [19] | a strong chance it's a common eastern bumblebee (Bombus impatiens). Yellow and |
| [20] | black striped with a rump covered in soft hairs, they're social insects that live in |
| [21] | colonies and love a good crevice—they build their homes in birdhouses, woodpiles, |
| [22] | abandoned burrows, and dense grasses. |
| [23] | [They] are important pollinators, both in the wild and in agriculture, where they're raised |
| [24] | and used to pollinate crops including tomatoes and pumpkins. Like other pollinators, |
| [25] | bumblebees face many threats, and C. bombi isn't even the biggest bumblebee |
| [26] | bugaboo. On its own, the parasite doesn't have much of an effect on a bumblebee's |
| [27] | health. But when food is scarce, C. bombi can shorten a bee's lifespan and even |
| [28] | reduce the number of young queens a colony can produce. |
| [29] | Lynn Adler is an evolutionary ecologist at the University of Massachusetts Amherst |
| [30] | who studies interactions between plants and insects. For years, she and longtime |
| [31] | collaborator Rebecca Irwin at North Carolina State University suspected pollinators |
| [32] | might be getting dosed by flowers since plants often invest chemically active |
| [33] | compounds into their nectar and pollen to help their genetic payload arrive at |
| [34] | its destination. |
| [35] | "Many plant defensive compounds can be medicinal at certain doses," Adler says. After |
| [36] | all, "most of our human medicines come from plants." |
| [37] | Giacomini discovered the effect of sunflower pollen as an undergraduate working in |
| [38] | Adler's lab in 2018. From [these] very first tests, sunflower pollen dramatically reduced |
| [39] | C. bombi parasite load in common eastern bumblebees, often clearing infection |
| [40] | completely. "We've been shocked at how consistent and effective sunflower pollen |
| [41] | has been," Adler says. |
| Elizabeth Anne Brown, National Geographic | |
How do bumblebees get rid of the parasites with the help of sunflower pollen?
Exani II, Exani II -> Estructura de la Lengua
Señale el sujeto que se encuentran en las siguientes oraciones:
En el mes de octubre, los médicos del Hospital darán varias consultas.
HISTORIA DE MÉXICO SIMULADOR PARA LA UNAM
¿Cuáles de los siguientes acontecimientos son propios del gobierno del general Lázaro Cárdenas?
I. Creación del banco nacional.
II. Expropiación petrolera.
III. Creación de la secretaria de educación pública.
IV. Creación del ejido colectivo.
V. Fomento de la construcción de presas.
VI. Organización de la conferencia de trabajadores en México.
Exani II, Exani II -> Pensamiento Analítico
¿Cuál es el significado del refrán?
Ojos que no ven, corazón que no siente.
HISTORIA UNIVERSAL SIMULADOR PARA LA UNAM
Selecciona los inventos científico-tecnológicos más importantes del Siglo XIX
Exani