FISICA SIMULADOR PARA LA UNAM
La potencia que requiere un montacargas para elevar un bloque de 2000N a una altura de 3m en 15s es de:
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 | |
What effect does sunflower pollen have on bumblebees?
Biología IPN
Ecosistema con árboles grandes y vegetación epífita que absorbe gases de efecto invernadero.
Exani II, Exani II -> Comprensión Lectora
Lee los siguientes textos y responde
Texto 1
Por contener gas, las bebidas de cola son ácidas (el ácido carbónico se forma cuando el dióxido de carbono se disuelve en agua) y pueden reaccionar violentamente con sales químicas como el bicarbonato de sodio. Muchas bebidas de cola también contienen ácido fosfórico o ácido cítrico, que incrementa altamente la acidez.
Texto 2
Los refrescos carbonatados pueden dañar el esmalte de los dientes y debilitarlo, lo que acaba facilitando la aparición de caries. Su contenido en grandes cantidades de azúcar, ácidos y gases es perjudicial para la salud dental e, incluso, de todo el organismo.
En conclusión podemos decir que:
GEOGRAFÍA SIMULADOR PARA LA UNAM
Las corrientes marinas frente a las costas de Japón favorecen el desarrollo de:
ESPAÑOL SIMULADOR PARA LA UNAM
En el enunciado:
¿No hemos oído hablar a alguien que PUGNA por expresarse correctamente?
Lo opuesto de la palabra en letras mayúsculas es
HISTORIA UNIVERSAL SIMULADOR PARA LA UNAM
Ordena cronológicamente los acontecimientos de la segunda
guerra mundial.
I. guerra civil española
II. invasión a Polonia
III. invasión a la URSS
IV. pearl harbor
V. bombas atómicas
Exani