Consider a food chain with 1,000 joules (an energy unit) available at the producer level. if this food chain is grass -> grasshopper -> lizard -> crow, how much energy is found at the level of the crow?

How do the sperm cells get from the stigma to the ovules? a. they slide down the petals to the bottom of the flower. b. they travel through pollen tubes. c. they travel along filaments. d. insects carry the sperm cells from the stigma to the ovules.